Using TempData, you may transfer temporary data between controllers in ASP.NET Core MVC. A dictionary called TempData can be used to transfer information between controllers both during the current request and the one that comes after. Here's how you can make this happen.

Configure the First Controller's TempData
Assign the data you wish to pass to the TempData in your first controller action.

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Create(Student student)
{
    if (ModelState.IsValid)
    {
        _context.Add(student);
        await _context.SaveChangesAsync();
        return RedirectToAction(nameof(Index));
    }
    // Transfer the Complete Student Object to the Teacher
    TempData["student"] = student;
    return RedirectToAction("Index","Teacher");
}

Complete Student Controller Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using DataTransferBetweenControllersinASPNETCoreMVC.DatbaseContext;
using DataTransferBetweenControllersinASPNETCoreMVC.Models;

namespace DataTransferBetweenControllersinASPNETCoreMVC.Controllers
{
    public class StudentsController : Controller
    {
        private readonly AppDbContext _context;

        public StudentsController(AppDbContext context)
        {
            _context = context;
        }

        // GET: Students
        public async Task<IActionResult> Index()
        {
            return View(await _context.Students.ToListAsync());
        }

        // GET: Students/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var student = await _context.Students
                .FirstOrDefaultAsync(m => m.Id == id);
            if (student == null)
            {
                return NotFound();
            }

            return View(student);
        }

        // GET: Students/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Students/Create
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create(Student student)
        {
            if (ModelState.IsValid)
            {
                _context.Add(student);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            // Transfer the Complete Student Object to Teacher
            TempData["student"] = student;
            return RedirectToAction("Index","Teacher");
        }

        // GET: Students/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var student = await _context.Students.FindAsync(id);
            if (student == null)
            {
                return NotFound();
            }
            return View(student);
        }

        // POST: Students/Edit/5
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("Id,Name,RollNo,Section,Program")] Student student)
        {
            if (id != student.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(student);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!StudentExists(student.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(student);
        }

        // GET: Students/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var student = await _context.Students
                .FirstOrDefaultAsync(m => m.Id == id);
            if (student == null)
            {
                return NotFound();
            }

            return View(student);
        }

        // POST: Students/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            var student = await _context.Students.FindAsync(id);
            if (student != null)
            {
                _context.Students.Remove(student);
            }

            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool StudentExists(int id)
        {
            return _context.Students.Any(e => e.Id == id);
        }
    }
}

Retrieve TempData in the Second Controller
In your second controller action, retrieve the TempData.
// GET: Teachers
public async Task<IActionResult> Index()
{
    // Recieve the Student Object data and then keep the data
    // Keep TempData for the next request
    var studentData = TempData["student"];
    TempData.Keep();
    return View(await _context.Teachers.ToListAsync());
}

Complete Teacher Controller Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using DataTransferBetweenControllersinASPNETCoreMVC.DatbaseContext;
using DataTransferBetweenControllersinASPNETCoreMVC.Models;

namespace DataTransferBetweenControllersinASPNETCoreMVC.Controllers
{
    public class TeachersController : Controller
    {
        private readonly AppDbContext _context;

        public TeachersController(AppDbContext context)
        {
            _context = context;
        }

        // GET: Teachers
        public async Task<IActionResult> Index()
        {
            // Recieve the Student Object data and then keep the data
            var studentData = TempData["student"];
            TempData.Keep();
            return View(await _context.Teachers.ToListAsync());
        }

        // GET: Teachers/Details/5
        public async Task<IActionResult> Details(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var teacher = await _context.Teachers
                .FirstOrDefaultAsync(m => m.Id == id);
            if (teacher == null)
            {
                return NotFound();
            }

            return View(teacher);
        }

        // GET: Teachers/Create
        public IActionResult Create()
        {
            return View();
        }

        // POST: Teachers/Create
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("Id,Name,Course,Department")] Teacher teacher)
        {
            if (ModelState.IsValid)
            {
                _context.Add(teacher);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            return View(teacher);
        }

        // GET: Teachers/Edit/5
        public async Task<IActionResult> Edit(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var teacher = await _context.Teachers.FindAsync(id);
            if (teacher == null)
            {
                return NotFound();
            }
            return View(teacher);
        }

        // POST: Teachers/Edit/5
        // To protect from overposting attacks, enable the specific properties you want to bind to.
        // For more details, see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(int id, [Bind("Id,Name,Course,Department")] Teacher teacher)
        {
            if (id != teacher.Id)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(teacher);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!TeacherExists(teacher.Id))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            return View(teacher);
        }

        // GET: Teachers/Delete/5
        public async Task<IActionResult> Delete(int? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var teacher = await _context.Teachers
                .FirstOrDefaultAsync(m => m.Id == id);
            if (teacher == null)
            {
                return NotFound();
            }

            return View(teacher);
        }

        // POST: Teachers/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(int id)
        {
            var teacher = await _context.Teachers.FindAsync(id);
            if (teacher != null)
            {
                _context.Teachers.Remove(teacher);
            }

            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool TeacherExists(int id)
        {
            return _context.Teachers.Any(e => e.Id == id);
        }
    }
}

Keeping TempData for Subsequent Requests
By default, TempData is meant for a single subsequent request. If you want to persist TempData for more than one subsequent request, you can use the Keep method.
// GET: Teachers
public async Task<IActionResult> Index()
{
    // Recieve the Student Object data and then keep the data
    var studentData = TempData["student"];
    TempData.Keep();
    return View(await _context.Teachers.ToListAsync());
}

Conclusion
TempData is an efficient way to pass temporary data across controllers in ASP.NET Core MVC. You can save and retrieve information for the current request and the one that follows using TempData. You can enable data sharing between several components of your application by setting TempData in one controller and retrieving it in another.

Keep in mind that TempData is only meant to be read once before being marked for deletion. If you need to store the data for more than one request, use the Keep method.

A handy way to share transient data between controllers when a user interacts with your ASP.NET Core MVC application is via TempData.

Developers can send calls to an API and receive results using Postman, a popular tool for testing APIs. It offers an easy-to-use interface for creating, testing, and documenting RESTful web services. We will look at using Postman for API testing in an ASP.NET MVC 5 application in this article.

Required conditions
    Postman installed on your computer and an ASP.NET MVC 5 project setup in Visual Studio
    basic familiarity with API development and ASP.NET MVC

Configuring the API
Step 1: Launch Visual Studio, then open the ASP.NET MVC 5 project template.
Step 2: Right-click on the "Controllers" folder and choose "Add" > "Controller" to add a new Controller to the project.

Step 3: Build and launch the program to make sure everything is operating as it should.

Postman is Used for API Testing
Step 1: Launch Postman and click the "New" dropdown menu, then choose "Request" to start a new request.
Step 2: Type your API endpoint's URL into the address bar.
Step 3: From the dropdown menu next to the address bar, choose the HTTP method you wish to use (GET, POST, PUT, DELETE, etc.).

Click on the appropriate tabs to add headers, query parameters, or request body data, if necessary.

Step 4: To send the request and get the answer, click the "Send" button.
The response's headers, content, and status code will all be shown in the lower panel.

Examining Various API Techniques

• GET Request: Just enter the API URL and choose the GET method to test a GET request. If necessary, you can add query parameters.
• POST Request: Choose the POST method and input the API URL to test a POST request. Using the "Body" tab, add request body data and select the desired format (x-www-form-urlencoded, form-data, raw, etc.).
• PUT Request: Choose the PUT method, input the API URL, and supply the request body data in order to test a PUT request.
• DELETE Request: Choose the DELETE method and input the API URL to test a DELETE request.

Managing the Authentication Process
You can add authentication headers or tokens in Postman if your API requires authentication. Before submitting the request, add the required authentication information in the "Authorization" or "Headers" tab.

Examining the Reaction
Postman presents the body, headers, and response status code in an organized manner. By examining the status code and contrasting it with the anticipated outcome, you may verify the response. You can also use XPath or JSONPath syntax to extract particular data from the response body.

Postman can make API testing more simpler and is a very useful tool for this purpose. In this post, we looked at using Postman to test an ASP.NET MVC 5 application's API. You may easily test various API methods, manage authentication, and examine the answer by following the above-described processes.

CORS: What is it?
CORS is a security feature of browsers that regulates the sharing of resources, such as images or data, across websites from different domains (e.g., example.com vs. api.example.com). In order to stop unwanted cross-domain queries, it enables servers to whitelist particular domains for resource access. Consider it a data passport that guarantees secure connections between websites.

Because browsers save a ton of personal information, such as cookies, for every website, CORS issues can be a pain. An unscrupulous website has the ability to take over your browser session and maybe steal sensitive data from reliable websites if CORS limitations are not properly implemented.

Set your server to accept requests from the origin of your front end to resolve CORS difficulties in Next.js and React.

We will set up our asp.net web API to do this in this tutorial.

Step 1: Create an attribute to handle and preprocess the request.

In the Generated Class File, add this code snippet.
public class AllowCrossSiteJsonAttribute : ActionFilterAttribute
{
    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        filterContext.RequestContext.HttpContext.Response.AddHeader("Access-Control-Allow-Origin", "*");
        base.OnActionExecuting(filterContext);
    }
}

Step 2. Bind with Action

[AllowCrossSiteJson]
public ActionResult About()
{
DataTable dms = repo.getpro();
string json = JsonConvert.SerializeObject(dms);
return Content(json);
}

We've tackled the notorious CORS beast in this article, explaining its complexities and giving you the tools to set up your ASP.NET MVC 5 Web API so that it works flawlessly with JavaScript frameworks like ReactJS. You've made it possible for secure, seamless communication between your dynamic client-side apps and your server-side API by putting these tips into practice.

Recall the main conclusions.

• Setting the right headers to allow cross-origin requests from the server side is known as "configuring access-control headers."

Keep in mind that security is crucial. As alluring as "AllowAnyOrigin" may be, think about customizing your CORS setup to meet your unique requirements so that only allowed origins have access to your sensitive information.

We really hope that this post has helped you in your CORS journey. Please feel free to post a remark below if you have any queries or difficulties, and our community will be pleased to help!

We will learn how to develop an ASP.NET Core MVC web application step by step in this tutorial. Web applications built with ASP.NET Core MVC are noted for their adaptability, scalability, and ability to meet a wide range of business requirements. By the end of this tutorial, you will have a firm grasp on the core principles and practical actions required to get started with your own ASP.NET Core MVC project.

What exactly is ASP.NET Core?
Microsoft's ASP.NET Core is an open-source, cross-platform framework for developing modern, cloud-based, and scalable online applications.

What are the benefits of using ASP.NET Core?

• ASP.NET Core is cross-platform, which means you can write and run applications on Windows, Linux, and macOS. Because of its adaptability, it is suited for a wide range of situations.
• High Performance: ASP.NET Core is built for speed and scalability. It employs asynchronous programming and supports real-time technologies such as WebSockets and SignalR.
• Open Source: Because ASP.NET Core is open source, you can view the source code and contribute to the community. It's being developed openly on GitHub, which encourages cooperation and improvement.
• ASP.NET Core emphasizes current development approaches such as dependency injection, integrated support for popular front-end frameworks such as Angular and React, and built-in support for RESTful APIs.
• Cross-platform Tools: ASP.NET Core comes with a set of cross-platform tools, including the .NET CLI, which simplifies development, testing, and deployment processes.
• Support for Microservices: ASP.NET Core is well-suited for microservices architecture, allowing you to build modular, independently deployable services that can scale individually.
• Integrated Security: ASP.NET Core provides built-in security features, such as identity and authentication, that help developers protect their applications against common threats.
• Extensible Middleware: Middleware in ASP.NET Core is highly customizable, allowing developers to add or remove components easily to tailor their application's behavior.
• Docker Support: ASP.NET Core has excellent support for Docker containers, making it straightforward to containerize your applications for easier deployment and scaling.

Step 2: Select a Project Template
All languages, All platforms, and All project kinds will be displayed. As seen in the figure below, I used the ASP.NET Core Web App (Model-View-Controller) Template.

After selecting a project template, click Next.
Step 3: Establish the Project Name and Location

The following options are available in the project configuration window:,

• Project Name: You can name your project whatever you want.
• Location: Select where you want to save the project files on your machine's hard drive. I chose the Project/VS folder on the machine's E drive, which is presumably different on your PC.
• Solution Name: The solution name is auto-generated based on the project name, but you can alter it to something else.

In addition, there is a checkbox. If you checked it, the solution file (.sln) and project files will be saved in the same directory. Now, select the bare minimum of details for clarity, as illustrated in the image below.

After defining the necessary details, click Next.

Step 4: Select a Target Framework
Choose the target framework.NET 6, which is the most recent, or choose according on your needs. Skip the rest of the details for clarity, as illustrated in the image below.

After providing the required details, click the Create button. It will create the ASP.NET Core MVC web application, as shown in step 5.

Step 5. Understanding ASP.NET Core MVC Folder Structure
The following is the default folder structure of the ASP.NET Core ASP.NET MVC application.

Let's understand the preceding project folder structure in brief.

In ASP.NET Core MVC, the project structure is organized to promote a clean and maintainable architecture. Here's a typical project structure for an ASP.NET Core MVC application.

• Controllers: This is where you define your controller classes. Controllers handle incoming HTTP requests and contain action methods.
• Models: In the Models folder, you define your data models. These models represent the structure of your application's data. You might have separate subfolders for different types of models (e.g., ViewModels, DataModels).
• Views: The Views folder is where you store your view files. These views are responsible for rendering the HTML that's sent to the client. You often have subfolders here corresponding to the controller names, which helps organize the views.
• wwwroot: This folder contains static files like CSS, JavaScript, and images that are directly accessible to the client.
• Startup.cs: This file contains the startup configuration for your application, including configuring services and middleware.
• appsettings.json: This JSON file is used to store configuration settings for your application, such as database connection strings.
• Program.cs: This is the entry point of your application. It contains the Main method that sets up the web host.
• wwwroot: This is where you place static files, such as CSS, JavaScript, and images, that are served directly to clients.
• Areas (optional): If you are using areas in your application to organize controllers and views, you will have a folder for each area.
• Data (optional): You can have a separate folder for data-related code, such as database context and migrations.
• Services (optional): You can create a folder for service classes that provide business logic and are used by your controllers.
• ViewComponents (optional): If you are using view components, you can organize them in this folder.
• Filters (optional): You may create custom action filters and store them in this folder.
• Extensions (optional): For extension methods and helper classes that can be reused throughout the application.
• Resources (optional): For storing localization resources if you are supporting multiple languages.
• Tests (optional): If you are writing unit tests, you can create a separate folder for your test projects.
• Properties (auto-generated): This folder may include the AssemblyInfo.cs file and other assembly-related information.

It's important to note that while this is a common structure, it's not set in stone, and you can adapt it to fit the specific requirements of your project. ASP.NET Core is flexible in this regard, allowing you to organize your code as you see fit while following best practices for maintainability and scalability.

Step 6. Run the ASP.NET Core MVC Application
You can run the application with default contents or let open the Index.cshtml file and put some contents there. Now press F5 on the keyboard or use the run option from Visual Studio to run the application in the browser. After running the application, it will show in the browser, as shown in the following image.

I hope you learnt how to develop the ASP.NET Core MVC Web Application from the accompanying step-by-step tutorial.

ASP.NET Core MVC (Model-View-Controller) is a sophisticated web application framework. It offers an organized approach to developing web applications by splitting application logic into separate components. When it comes to data access, developers have several options. Dapper, a lightweight and efficient Object-Relational Mapping (ORM) library, is one of the more popular choices.

In this post, we'll look at how to build a comprehensive CRUD (Create, Read, Update, Delete) application with ASP.NET Core MVC and Dapper, combining the characteristics of both technologies to create a strong web application.

What exactly is Dapper?
Dapper is a.NET micro ORM library created by the Stack Overflow team. Dapper, in contrast to full-featured ORMs such as Entity Framework, keeps things simple and lightweight. It allows you to map database records to.NET objects without adding unnecessary complexity. Dapper is well-known for its speed and efficiency, making it an ideal candidate for high-performance applications.

Using ASP.NET Core MVC with Dapper to Create a CRUD Application

You'll need the following components to construct a comprehensive CRUD application with ASP.NET Core MVC and Dapper:

• Visual Studio or any other code editor will suffice.
• SQL Server or another database server may be used.
• ASP.NET Core MVC application.

Let us now begin the process.

Make an ASP.NET Core MVC Project.
Begin by launching Visual Studio and creating a new ASP.NET Core MVC project. You can select the "Web Application" template and the "MVC" project type.

Step 1

Step 2

Step 3

Install Dapper
Install the Dapper library via NuGet Package Manager.

Database Interconnection
Connect to your SQL Server via a database connection. To connect to the database, use the connection string in your application.
Step 1. Launch SQL Server Management Studio (SSMS).
Step 2: Establish a connection to a SQL Server instance by entering the server name and authentication credentials.
Step 3: In the Object Explorer, right-click on the destination server's "Databases" folder and select "New Database."

Step 4: In a SQL Server database, follow these steps to build a table and CRUD (build, Read, Update, Delete) stored procedures for that table.
Make a Table
CREATE TABLE dbo.Person(
Id INT PRIMARY KEY IDENTITY,
FullName NVARCHAR (100) NOT NULL,
Email NVARCHAR (100) NOT NULL,
[Address] NVARCHAR (200) NOT NULL
);

Create CRUD Stored Procedures

/* CREATE OPERATION */
CREATE PROCEDURE sp_add_person(
    @name NVARCHAR(100),
    @emil NVARCHAR(100),
    @address NVARCHAR(200)
)
AS
BEGIN
    INSERT INTO dbo.Person (FullName, Email, [Address])
    VALUES (@name, @emil, @address)
END

/* READ OPERATION */
CREATE PROCEDURE sp_get_Allperson
AS
BEGIN
    SELECT * FROM dbo.Person
END

/* UPDATE OPERATION */
CREATE PROCEDURE sp_update_person(
    @id INT,
    @name NVARCHAR(100),
    @email NVARCHAR(100),
    @address NVARCHAR(200)
)
AS
BEGIN
    UPDATE dbo.Person
    SET FullName = @name, Email = @email, [Address] = @address
    WHERE Id = @id
END

/* DELETE OPERATION */
CREATE PROCEDURE sp_delete_person(@id INT)
AS
BEGIN
    DELETE FROM dbo.Person WHERE Id = @id
END

Create a Data Access Layer
Start by Adding a new Class Library project to your project.

Step 1

Step 2

Step 3. Define a model class to represent the data you want to manipulate.

public class Person
    {
        public int Id { get; set; }
        [Required]
        public string? FullName { get; set; }
        [Required]
        public string? Email { get; set; }
        public string? Address { get; set; }
    }

Step 4: Using Dapper, create a data access layer. This layer will include methods for carrying out CRUD tasks on your model objects.

using Microsoft.Extensions.Configuration;
using Dapper;
using Microsoft.Data.SqlClient;
using System.Data;

namespace DapperMVC.Data.DataAccess
{
    public class SqlDataAccess: ISqlDataAccess
    {
        private readonly IConfiguration _configuration;
        public SqlDataAccess(IConfiguration configuration)
        {
            _configuration = configuration;
        }
        public async Task<IEnumerable<T>> GetData<T, P>(string spName, P parameters, string connectionId = "conn")
        {
            try {
                string connectionString = _configuration.GetConnectionString(connectionId);
                using (IDbConnection dbConnection = new SqlConnection(connectionString))
                {
                    return await dbConnection.QueryAsync<T>(spName, parameters, commandType: CommandType.StoredProcedure);
                }
            }
            catch (Exception ex)
            {
                throw;
            }

        }
        public async Task<bool> SaveData<T>(string spName, T parameters, string connectionId = "conn")
        {
            try
            {
                using IDbConnection connection = new SqlConnection(_configuration.GetConnectionString(connectionId));
                await connection.ExecuteAsync(spName, parameters, commandType: CommandType.StoredProcedure);
                return true;
            }
            catch (Exception ex)
            {

                return false;
            }
        }
    }
}

using DapperMVC.Data.DataAccess;
using DapperMVC.Data.Models.DbModel;
using Microsoft.Extensions.Configuration;

namespace DapperMVC.Data.Repository
{
    public class PersonRepository : IPersonRepository
    {
        private readonly ISqlDataAccess _dataAccess;
        private readonly IConfiguration _configuration;
        public PersonRepository(ISqlDataAccess db, IConfiguration configuration)
        {
            _dataAccess = db;
            _configuration = configuration;
        }
        public async Task<bool> AddAsync(Person person)
        {
            try
            {
                await _dataAccess.SaveData("sp_add_person", new
                {
                    Name = person.FullName,
                    email = person.Email,
                    address = person.Address
                });
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }
        public async Task<bool> UpdateAsync(Person person)
        {
            try
            {
                await _dataAccess.SaveData("sp_update_person", new
                {
                    id = person.Id,
                    Name = person.FullName,
                    email = person.Email,
                    address = person.Address
                });
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }
        public async Task<bool> DeleteAsync(int id)
        {
            try
            {
                await _dataAccess.SaveData("sp_delete_person", new { Id = id });
                return true;
            }
            catch (Exception ex)
            {
                return false;
            }
        }
        public async Task<Person?> GetByIdAsync(int id)
        {
            IEnumerable<Person> result = await _dataAccess.GetData<Person, dynamic>
                ("sp_get_person", new { Id = id });
            return result.FirstOrDefault();
        }
        public async Task<IEnumerable<Person>> GetAllPersonAsync()
        {
            string query = "sp_get_Allperson";
            return await _dataAccess.GetData<Person, dynamic>(query, new { });
        }
    }
}

Actions of the Controller
Make controller actions that communicate with your data access layer. These actions will process requests, call the appropriate data access methods, and return views.

public IActionResult Person()
{
    return View();
}

[HttpGet]
public async Task<IActionResult> Add()
{
    return View();
}

[HttpPost]
public async Task<IActionResult> Add(Person person)
{
    try
    {
        if (!ModelState.IsValid)
        {
            return View(person);
        }
        bool addPerson = await _personRepo.AddAsync(person);
        if (addPerson)
        {
            TempData["msg"] = "Successfully Added";
        }
        else
        {
            TempData["msg"] = "Could Not Added";
        }
    }
    catch (Exception ex)
    {
        TempData["msg"] = "Could Not Added";
    }
    return RedirectToAction(nameof(Add));
}

[HttpGet]
public async Task<IActionResult> Edit(int id)
{
    var person = await _personRepo.GetByIdAsync(id);
    if (person == null)
    {
        throw new Exception();
    }
    return View("Edit", person);
}

[HttpPost]
public async Task<IActionResult> Edit(Person person)
{
    try
    {
        if (!ModelState.IsValid)
        {
            return View(person);
        }
        var updateResult = await _personRepo.UpdateAsync(person);
        if (updateResult)
        {
            TempData["msg"] = "Edit Successfully.";
            return RedirectToAction(nameof(DisplayAllPerson));
        }
        else
        {
            TempData["msg"] = "Could Not Edit.";
            return View(person);
        }
    }
    catch (Exception ex)
    {
        TempData["msg"] = "Could Not Edit.";
        return View(person);
    }
}

[HttpGet]
public async Task<IActionResult> DisplayAllPerson()
{
    try
    {
        var personAll = await _personRepo.GetAllPersonAsync();
        return View(personAll);
    }
    catch (Exception ex)
    {
        return View("Error", ex);
    }
}

[HttpGet]
public async Task<IActionResult> Delete(int id)
{
    var deleteResult = await _personRepo.DeleteAsync(id);
    return RedirectToAction(nameof(DisplayAllPerson));
}

Views
Create views for your controller actions. You can use Razor views to generate HTML content and display data to users.

Implement the CRUD Operations
Create controller actions and views to handle Create, Update, and Delete operations. You'll need forms in your views for creating and editing data and buttons or links to delete records.

Test and Debug
Test your application thoroughly, making sure all CRUD operations work as expected. Debug any issues that arise.

Output

When paired with Dapper, ASP.NET Core MVC provides a robust and efficient framework for developing CRUD apps. Because of Dapper's lightweight and high-performance data access capabilities, it is an excellent solution for applications that require speed and simplicity. You can construct a powerful CRUD application that properly manages data and delivers a seamless user experience by following the steps indicated in this article. As you gain experience with Dapper and ASP.NET Core MVC, you can add more features and functionalities to your application.

ASP.NET MVC (Model-View-Controller) is a popular web development framework for creating strong and maintainable web applications. Model Binders are an important part of it. Model Binders play a critical role in mapping incoming HTTP requests to action method parameters, making it easier to work with client-side data. In this blog post, we will delve into the world of ASP.NET MVC Model Binders and present practical examples of how to use them.

What Exactly Are Model Binders?
Model Binders are ASP.NET MVC components that are responsible for mapping data from numerous sources, such as form fields, query strings, route parameters, and JSON payloads, to action method parameters. They are critical in easing the process of taking user input and transforming it into highly typed objects that your program may use.

Here's a detailed breakdown of how Model Binders work:

• A user delivers an HTTP request to your ASP.NET MVC application, generally via a form submission or an API call.
• Routing: The MVC framework uses routing rules to identify which controller and action method should handle the request.
• Model Binders are useful in this situation. They collect data from the HTTP request and transfer it to the action method's arguments. The mapping is based on the names and types of parameters.
• Execution of Action Methods: After the data is bound to the action method parameters, the method is executed using the provided data.
• The action method processes the data and provides a response, which is returned to the client.

Now, let's look at some real-world examples of Model Binders.

Binding to Simple Types as an Example
Assume you have a simple HTML form with a single text input field named "username." You wish to capture the user's entered username.
public ActionResult Register(string username)
{
    // Process the username
    return View();
}

In this scenario, the Model Binder automatically binds the username parameter based on the name of the form input field.

Example 2: Complex Type Binding
Model Binders can also be used to tie complex types, such as custom classes, to action method parameters. Consider the following User class:

public class User
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
}

You can bind an instance of the User class from a form submission as follows:
public ActionResult CreateUser(User user)
{
    // Process the user object
    return View();
}

The Model Binder will automatically populate the User object's properties using the submitted form data.
Example 3. Custom Model Binders

In some cases, you might need to implement custom Model Binders to handle complex scenarios. For example, if you want to bind data from a non-standard source or perform custom data transformation, you can create a custom Model Binder.
public class CustomBinder : IModelBinder
{
    public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
    {
        // Custom logic to bind the model
        // Example: Read data from a cookie and populate the model
    }
}

To use the custom Model Binder, you can decorate your action method parameter with the [ModelBinder] attribute:

public ActionResult MyAction([ModelBinder(typeof(CustomBinder))] MyModel model)
{
    // Custom binding logic applied
    return View();
}

ASP.NET MVC Model Binders are critical components that let you manage user input data in your online applications. They make it simple to convert HTTP request data to action method parameters, making it easier to work with user-supplied data. Model Binders provide a strong technique for streamlining data binding in your ASP.NET MVC applications, whether you're dealing with simple types or complex objects.

You can design more efficient and maintainable web apps with ASP.NET MVC if you understand how Model Binders function and use them effectively.

In this article, we are going to learn how to use elastic search with ASP.NET MVC in step by step way.We are already in the fifth part of this article. Till now, we have covered a lot in elastic search starting from how to configure elastic search to how to insert data into elastic search, further using Kibana for visualizing data, and at last, we have learned about Logstash and how to insert a bulk of data from MSSQL and MYSQL into elastic search. Now, it’s time to learn how we can query elastic search documents from ASP.NET MVC because at last, we need to show data to end-users in a fast way as possible.

If you are a beginner and you do not have an idea what is elastic search but you want to know it, then the below links will help you to kick start with elastic search.

Create ASP.NET MVC Application
Let’s create a simple ASP.NET MVC application with the name “WebElasticSearch”.

After entering the name, it will show another window for project selection. There, just choose “MVC” Template and change Authentication to “No Authentication” and click OK to create the project.

Project Structure

Next, we are going to install NuGet packages.            

Installing NuGet Packages

We are going to install 2 NuGet packages.

    Net
    Nest

After installing the NuGet package, next, we are going to add a new connection folder.
Creating Connector folder and adding ConnectionToEs class

After creating the folder, next, we are going to add ConnectionToEs class.
In this class, we are going to create a connection to elastic search instance. As you can see in the below code, we have provided elastic search URI http://localhost:9200/".

Code Snippet

    using Elasticsearch.Net;  
    using Nest;  
    using System;  
    using System.Collections.Generic;  
    using System.Linq;  
    using System.Web;  
      
    namespace WebElasticSearch.Connector  
    {  
        public class ConnectionToEs  
        {  
            #region Connection string to connect with Elasticsearch  
      
            public ElasticClient EsClient()  
            {  
                var nodes = new Uri[]  
                {  
                    new Uri("http://localhost:9200/"),  
                };  
      
                var connectionPool = new StaticConnectionPool(nodes);  
                var connectionSettings = new ConnectionSettings(connectionPool).DisableDirectStreaming();  
                var elasticClient = new ElasticClient(connectionSettings);  
      
                return elasticClient;  
            }  
     
            #endregion Connection string to connect with Elasticsearch  
        }  
    }  

After creating the connection class, next, we are going to add a Controller and create View for search.

Add Controller “AllSearch”

Adding a controller with name “AllSearch”.

After adding the Controller, next, we are going to add an action method and in the constructor, we are going to instantiate the connection object.

Adding Action Method
In this part, we are going to add Action method “Search” and create an instance of the ConnectionToEs class.

Code Snippet
    using System.Web.Mvc;  
    using WebElasticSearch.Connector;  
      
    namespace WebElasticSearch.Controllers  
    {  
        public class AllSearchController : Controller  
        {  
            private readonly ConnectionToEs _connectionToEs;  
            public AllSearchController()  
            {  
                _connectionToEs = new ConnectionToEs();  
            }  
      
            [HttpGet]  
            public ActionResult Search()  
            {  
                return View("Search");  
            }  
        }  
    }  

After adding “Search” Action Method, we are going to add a View for that action method.

Now, we are going to design the View.

Designing View

In this part, we are going to design the View with 2 textboxes.

    jobtitle
    nationalidnumber

Below is document of “humanresource” index in which, first we are going to create a search on both these parameters.

After designing the search View, next, we are going to add a class “humanresource” and properties similar to “humanresource” index and type “doc”.

Adding Class similar to “Humanresource” Index and type “Doc”
    public class Humanresources  
    {  
     public string nationalidnumber { get; set; }  
     public string LoginID { get; set; }  
     public string OrganizationNode { get; set; }  
     public int? OrganizationLevel { get; set; }  
     public string jobtitle { get; set; }  
     public string BirthDate { get; set; }  
     public string MaritalStatus { get; set; }  
     public string Gender { get; set; }  
     public DateTime? HireDate { get; set; }  
     public bool? SalariedFlag { get; set; }  
     public int? VacationHours { get; set; }  
     public int? SickLeaveHours { get; set; }  
     public bool? CurrentFlag { get; set; }  
     public string rowguid { get; set; }  
     public DateTime? ModifiedDate { get; set; }  }

After adding humanresource class next we are going to add “DataSearch” Action Method which will take both this parameter as input and provide response in json.

Adding DataSearch Action Method
The request to elastic search we are going to send using “Nest” Client.

In this action Method the first thing we have done is to connect to elastic search using connectionEs class, then we have provided index “humanresources” and type “doc”, next we can provide size of document as output I have provided as 50, at last comes query in this we are using “match” query for that we are passing field jobtitle and in query we are going to pass value which we have searched.

Code Snippet
    public JsonResult DataSearch(string jobtitle, string nationalIDNumber)  
        {  
            var responsedata = _connectionToEs.EsClient().Search<Humanresources>(s => s  
                                    .Index("humanresources")  
                                    .Type("doc")  
                                    .Size(50)  
                                    .Query(q => q  
                                        .Match(m => m  
                                            .Field(f => f.jobtitle)  
                                            .Query(jobtitle)  
                                        )  
                                    )  
                                );  
      
            var datasend = (from hits in responsedata.Hits  
                            select hits.Source).ToList();  
      
            return Json(new { datasend, responsedata.Took }, behavior: JsonRequestBehavior.AllowGet);  
        }  

After creating Action Method and setting up search with Nest, next we are going to call this Action Method using AJAX and then display this result on View. Since we get the response as JSON, I am going to use a client-side grid from DevExpress.

Calling Datasearch Action Method using Ajax and Displaying Response in Grid

Code Snippet
    <script>  
        $(document).ready(function () {  
      
            $("#btnsubmit").on("click", function () {  
      
                if ($("#txtjobTitle").val() === "" && $("#txtnationalIDNumber").val() === "") {  
                    alert("Provide Details to Search !");  
                }  
                else {  
      
                    var obj = {};  
                    obj.jobTitle = $.trim($("#txtjobTitle").val());  
                    obj.nationalIDNumber = $.trim($("#txtnationalIDNumber").val());  
      
                    var apiUrl = "@Url.Action("DataSearch", "AllSearch")";  
      
                    $.ajax({  
                        type: "POST",  
                        contentType: 'application/json',  
                        url: apiUrl,  
                        dataType: "json",  
                        data: JSON.stringify(obj),  
                        crossDomain: true,  
                        success: function (data) {  
                            var response = data;  
      
                            if (data.datasend.length <= 0) {  
                                alert("No Data Found!!");  
                            } else {  
      
                                var timetook = data.Took;  
                                $('div.total-title').text(timetook + " millisecond");  
      
                                $("#gridContainer").dxDataGrid({  
                                    dataSource: data.datasend,  
                                    showColumnLines: false,  
                                    showRowLines: true,  
                                    rowAlternationEnabled: true,  
                                    showBorders: true,  
                                    paging: {  
                                        pageSize: 50  
                                    },  
                                    scrolling: {  
                                        mode: "infinite" // or "virtual" | "infinite"  
                                    },  
                                    pager: {  
                                        showPageSizeSelector: false,  
                                        allowedPageSizes: [5, 10, 20],  
                                        showInfo: true  
                                    },  
                                    columns: [  
                                        {  
                                            caption: "JobTitle",  
                                            width: 350,  
                                            fixed: true,  
                                            dataField: "jobtitle"  
                                        },  
                                        {  
                                            caption: "NationalIDNumber",  
                                            width: 300,  
                                            fixed: true,  
                                            dataField: "nationalidnumber"  
                                        },  
                                         "MaritalStatus",  
                                         "Gender",  
                                         "SalariedFlag",  
                                         "VacationHours",  
                                         "SickLeaveHours",  
                                         "CurrentFlag"  
                                    ]  
                                });  
      
                            }  
                        },  
                        error: function (xhr, err) {  
                            alert("readyState: " + xhr.readyState + "\nstatus: " + xhr.status);  
                            alert("responseText: " + xhr.responseText);  
                        }  
      
                    });  
      
                }  
      
            });  
      
        });  
      
    </script>  

Markup of Grid
    <div class="panel panel-default">  
        <div class="panel-heading">Output</div>  
        <div class="panel-body">  
            <div class="row">  
                <div class="col-lg-12">  
                    <div id="gridContainer"></div>  
                </div>  
            </div>  
        </div>  
    </div>   

We have set up everything. Let’s run the code and see the output.

Output

Let’s see in Debug Mode how it works.

Searching Values

Getting Response

Single Document View

Let us now make the search conditional, i.e., the user can use any combination to search.

If the user searches data by Jobtitle only, then he will get response according to jobtitle. If a user does search with nationalidnumber, then he will get response according to it. Finally, the combination of both (Jobtitle+ nationalidnumber) can also be used to search, then the user will get response according to it.

Code Snippet
    public JsonResult DataSearch(string jobtitle, string nationalIDNumber)  
          {  
      
              if (!string.IsNullOrEmpty(jobtitle) && !string.IsNullOrEmpty(nationalIDNumber))  
              {  
                  var responsedata = _connectionToEs.EsClient().Search<Humanresources>(s => s  
                                   .Index("humanresources")  
                                   .Type("doc")  
                                   .Size(50)  
                                   .Query(q => q  
                                       .Match(m => m  
                                           .Field(f => f.jobtitle)  
                                           .Query(jobtitle)  
                                       )  
                                       && q  
                                       .Match(m => m  
                                           .Field(f => f.nationalidnumber)  
                                           .Query(nationalIDNumber)  
                                   ))  
                               );  
      
                  var datasend = (from hits in responsedata.Hits  
                                  select hits.Source).ToList();  
      
                  return Json(new { datasend, responsedata.Took }, behavior: JsonRequestBehavior.AllowGet);  
      
              }  
              else if (!string.IsNullOrEmpty(jobtitle))  
              {  
                  var responsedata = _connectionToEs.EsClient().Search<Humanresources>(s => s  
                                  .Index("humanresources")  
                                  .Type("doc")  
                                  .Size(50)  
                                  .Query(q => q  
                                      .Match(m => m  
                                          .Field(f => f.jobtitle)  
                                          .Query(jobtitle)  
                                      )));  
      
                  var datasend = (from hits in responsedata.Hits  
                                  select hits.Source).ToList();  
      
                  return Json(new { datasend, responsedata.Took }, behavior: JsonRequestBehavior.AllowGet);  
              }  
              else if (!string.IsNullOrEmpty(nationalIDNumber))  
              {  
                  var responsedata = _connectionToEs.EsClient().Search<Humanresources>(s => s  
                                  .Index("humanresources")  
                                  .Type("doc")  
                                  .Size(50)  
                                  .Query(q => q  
                                      .Match(m => m  
                                          .Field(f => f.nationalidnumber)  
                                          .Query(nationalIDNumber)  
                                      )));  
                  var datasend = (from hits in responsedata.Hits  
                                  select hits.Source).ToList();  
      
                  return Json(new { datasend, responsedata.Took }, behavior: JsonRequestBehavior.AllowGet);  
              }  
              return Json(data: null, behavior: JsonRequestBehavior.AllowGet);  
      
          }  

Output

These are simple examples which will help you to start using elastic search with ASP.NET Application. There are lots of filters and ways to write query in Elastic using “Nest” in ASP.NET.

Finally, we have learned how to simply query elastic search using “Nest” Client and display data in grid.

Step: Design your Database
Create the UserProfile table using the following script.
    Create Table UserProfile  
        (  
            UserId int primary key identity(1, 1),  
            UserName varchar(50),  
            Password varchar(50),  
            IsActive bit  
        ) 

Insert user records using the following script.
    Insert into UserProfile  
    Select 'peter', 'pete1234', 1 Union All  
    Select 'scott', 'scott1234', 1 Union All  
    Select 'laura', 'laura1234', 1

Step 1: Create Project
Go to FILE, New, then click on Project.

Select Visual C#, Web under Installed templates. After that select ASP.NET MVC Web Application, then mention the Application Name (MvcLoginAppDemo) and Solution Name as you wish, then click OK.

Under Project template select a template as Basic, then Click OK.

Step 2: Add Entity Data Model
Go to Solution Explorer, Right Click on Project, Add, then select ADO.NET Entity Data Model.

Give it a meaningful model name and then click on Add.

Select Generate from database and then click on Next.

Click on New Connection,

After clicking on New Connection, we have to provide the following Connection Properties in the following wizard.
    Provide the Server name.
    Select the "Use SQL Server Authentication" radio button.
    Enter the User name and Password in the password text box.
    Check the "Save my password" checkbox.
    Select the "Select or enter a database name:" radio button.
    Select the database to which you want to set the connection.
    Click on the "Test Connection" button to ensure the connection can be established.
    Then click OK.

Select radio button: Yes include the sensitive data in the connection string. Choose your database objects, as in the following image. Click on Finish. At this point UserProfie entity will be created.

Step 3: Add a Controller
Go to Solution Explorer, Right click on Controller folder, Add and then click on Controller.
( Or ) Simply use shortcut key Ctrl + M, Ctrl + C,

Provide the Controller Name, and Scaffolding template as Empty MVC Controller. Then click on Add.

Write the following code in HomeController.
    using System.Linq;  
    using System.Web.Mvc;  
      
    namespace MvcLoginAppDemo.Controllers  
    {  
        public class HomeController: Controller  
        {  
            public ActionResult Login()  
            {  
                return View();  
            }  
      
            [HttpPost]  
            [ValidateAntiForgeryToken]  
            public ActionResult Login(UserProfile objUser)   
            {  
                if (ModelState.IsValid)   
                {  
                    using(DB_Entities db = new DB_Entities())  
                    {  
                        var obj = db.UserProfiles.Where(a => a.UserName.Equals(objUser.UserName) && a.Password.Equals(objUser.Password)).FirstOrDefault();  
                        if (obj != null)  
                        {  
                            Session["UserID"] = obj.UserId.ToString();  
                            Session["UserName"] = obj.UserName.ToString();  
                            return RedirectToAction("UserDashBoard");  
                        }  
                    }  
                }  
                return View(objUser);  
            }  
      
            public ActionResult UserDashBoard()  
            {  
                if (Session["UserID"] != null)  
                {  
                    return View();  
                } else  
                {  
                    return RedirectToAction("Login");  
                }  
            }  
        }  
    }  

Step 4: Create Views
Create View for Login Action Method
 
Right click on the Login Action method, then click on Add View as in the following picture.

Create Strongly Typed View
    View Name must be an action method name.
    Select view engine as Razor.
    Select Create a strongly typed view CheckBox .
    Select Model class as UserProfile (MvcLoginAppDemo)
    Select Scaffold template as Empty
    Click on Add

And write the following code in Login.cshtml (view).
    @model MvcLoginAppDemo.UserProfile  
      
    @{  
    ViewBag.Title = "Login";  
    }  
      
    @using (Html.BeginForm("Login", "Home", FormMethod.Post))  
    {  
    <fieldset>  
    <legend>Mvc Simple Login Application Demo</legend>  
      
    @Html.AntiForgeryToken()  
    @Html.ValidationSummary(true)  
    @if (@ViewBag.Message != null)  
    {  
    <div style="border: 1px solid red">  
    @ViewBag.Message  
    </div>  
    }  
    <table>  
    <tr>  
    <td>@Html.LabelFor(a => a.UserName)</td>  
    <td>@Html.TextBoxFor(a => a.UserName)</td>  
    <td>@Html.ValidationMessageFor(a => a.UserName)</td>  
    </tr>  
    <tr>  
    <td>  
    @Html.LabelFor(a => a.Password)  
    </td>  
    <td>  
    @Html.PasswordFor(a => a.Password)  
    </td>  
    <td>  
    @Html.ValidationMessageFor(a => a.Password)  
    </td>  
    </tr>  
    <tr>  
    <td></td>  
    <td>  
    <input type="submit" value="Login" />  
    </td>  
    <td></td>  
    </tr>  
    </table>  
    </fieldset>  
    }  

Create View for UserDashBoard Action method same as login view. And write the following code in UserDashBoard.cshtml (View).
    @ {  
        ViewBag.Title = "UserDashBoard";  
    }  
      
    < fieldset >  
        < legend > User DashBoard < /legend>  
      
    @if(Session["UserName"] != null) { < text >  
            Welcome @Session["UserName"].ToString() < /text>  
    } < /fieldset>  

Step 5: Set as StartUp Page
Go to Solution Explorer, Project, App_Start, then RouteConfig.cs  and change the action name from Index to Login (Login.cshtml as start up page).

Step 6: Run the Application
Provide the user credentials and click on OK. If you provide the valid user credentials then the user name will be displayed on your dashboard.

In this post, I'll show you how to use an ASP.NET MVC application to establish a WEBAPI POST function to extract data from a SQL database.

Open SQL Management Studio, then create a new table and write the table's stored procedure.
Table column names and datatypes are determined by your needs.

Create proc [dbo].[UserInfo]
(
@UserName nvarchar(100)
)
as
(
select UserId,UserName,Address,IsActive,UserTypeId from WebAPI
where
UserName=@UserName
)

Once you have successfully created the SQL store procedure then Create a new MVC WebAPI Application using visual studio.
provide the project name and project location.

Choose Empty project, then select the MVC and WEB API options from the essential references column on the right.

Now the project has been created successfully.

After you've created the project, right-click on the Models folder, select Add, and then New item. In the Models Folder, place the class file.

From the C# node then choose the class definition and provide the class file name UserEntity.cs. Once we added the class file to our project solution.

Use the below code in UsersEntity.cs file.
using Microsoft.SqlServer.Server;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.Headers;
using System.Net.Http;
using System.Threading.Tasks;
using System.Web;
using System.Web.UI.WebControls;
using Microsoft.Office.SharePoint.Tools;
using static System.Net.Mime.MediaTypeNames;
using System.Data;

namespace SampleWebAPI.Models
{
    public class UsersEntity
    {

        public string UserId { get; set; }

        public string UserName { get; set; }

        public string Address { get; set; }

        public string UserTypeId { get; set; }

        public string IsActive { get; set; }

        public UsersEntity()
        {

        }
     }

}

Likewise create a new logger.cs and ErrorDetails.cs class file to capture the logs and error details in the Models folder.

Use the below code in Logger.cs file.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace SampleWebAPI.Models
{
    public class Logger
    {
         // To capture the log details
        #region "-- Class Level Variable / Object Declaration --"
        private static readonly log4net.ILog logger = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);
        #endregion
        #region "-- Public Functions --"
        public static void LogError(string msg, Exception ex)
        {
            logger.Error(msg, ex); //This for error msg
        }
        public static void LogDebug(string msg, Exception ex)
        {
            logger.Debug(msg, ex);
        }
        public static void LogFatal(string msg, Exception ex)
        {
            logger.Fatal(msg, ex);
        }
        public static void LogInfo(string msg)
        {
            logger.Info(msg);
        }
        public static void LogWarn(string msg, Exception ex)
        {
            logger.Warn(msg, ex);
        }
        public static void LogInfo(string msg, Exception ex)
        {
            logger.Info(msg, ex);
        }
    }
    #endregion
}

Use the below code in ErrorDetails.cs file.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace SampleWebAPI.Models
{
//This Class used for error msg
    public class ErrorDetails
    {
        public List<string> schemas { get; set; }
        public string details { get; set; }
        public int status { get; set; }
    }
}

Then add the controller to the Controller folder.
Right Click on the Controller folder, choose to add, and click Controller.
Click the MVC empty read and write controller file.

Then give the controller name based on your requirement.

Once the Controller has been created successfully, we can write the Controller methods in the controller.
Use the below code in the controller.
using Newtonsoft.Json.Linq;
using Newtonsoft.Json;
using SampleWebAPI.Models;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Data;
using System.Linq;
using System.Net;
using System.Web;
using System.Web.Http;
using System.Web.Mvc;
using System.Web.UI.WebControls;
using Microsoft.Office.SharePoint.Tools;
using static System.Net.Mime.MediaTypeNames;

namespace SampleWebAPI.Controllers
{
    public class UserController : ApiController // To Initialize the Web API
    {
        [System.Web.Http.AcceptVerbs("GET", "POST")] // To check the result in browser
        [System.Web.Http.HttpPost] //To check the Post method
        [System.Web.Http.Route("users/info")] //This the route url
        public JObject info(string UserName)
        {
            ErrorDetails objErrorDetail = new ErrorDetails();
            string jsonResponse = string.Empty;
            JObject jsonObject = null;


            try
            {
                Logger.LogInfo("info: starting to get user list info");
                DataSet ds = new DataSet();
                UsersEntity objUserDetail = new UsersEntity();
                SqlConnection conn = new SqlConnection();
                conn.ConnectionString ="Data Source=Test;" +"Initial Catalog=Test;" +"User id=Test;" + "Password=Test;";

                {
                  //Sql connection from the database
                    using (SqlCommand cmd = new SqlCommand("UserInfo", conn))
                    {
                        conn.Open();
                        Logger.LogInfo("info: Sql Connection established.");
                        cmd.CommandType = CommandType.StoredProcedure;
                        cmd.Parameters.AddWithValue("@UserName",UserName);
                        SqlDataAdapter da = new SqlDataAdapter(cmd);
                        da.Fill(ds);
                        conn.Close();
                        Logger.LogInfo("info: Sql Connection closed.");

                    }
                }

                if (ds.Tables[0].Rows.Count >= 1)
                {
                    Logger.LogInfo("info: starting to format the json.");
                    foreach (DataRow dr in ds.Tables[0].Rows)
                    {
                        // Display the column in the output page using object dataset.
                        List<string> lst = new List<string>();
                        objUserDetail.UserName = dr["UserName"].ToString();
                        objUserDetail.UserId = dr["UserId"].ToString();
                        objUserDetail.Address = dr["Address"].ToString();
                        objUserDetail.UserTypeId = dr["UserTypeId"].ToString();
                        objUserDetail.IsActive = dr["IsActive"].ToString();
                        jsonResponse = JsonConvert.SerializeObject(objUserDetail);
                        // Deserialize the JSON API response into a JObject
                        jsonObject = JsonConvert.DeserializeObject<JObject>(jsonResponse);
                        // Serialize the updated object back to JSON
                        string updatedJsonResponse = jsonObject.ToString();

                    }
                    Logger.LogInfo("info: data formatted in json successfuly.");
                    return jsonObject;
                }
                else
                {
                    Logger.LogInfo("info: User not found returned null data.");
                    List<string> lst = new List<string>();
                    lst.Add("urn:ietf:params:scim:api:messages:2.0:Error");
                    objErrorDetail.schemas = lst;
                    objErrorDetail.status = (int)HttpStatusCode.NotFound;
                    objErrorDetail.details = "User Not Found";
                    return JsonConvert.DeserializeObject<JObject>(JsonConvert.SerializeObject(objErrorDetail));
                }
            }
            catch (Exception ex)
            {
                Logger.LogInfo("info: Error occured.");
                Logger.LogError("info: Error - " + ex.Message, ex);
                jsonObject = null;
                List<string> lst = new List<string>();
                lst.Add("urn:ietf:params:scim:api:messages:2.0:Error");
                objErrorDetail.schemas = lst;
                objErrorDetail.status = (int)HttpStatusCode.InternalServerError;
                objErrorDetail.details = ex.Message.ToString();
                return JsonConvert.DeserializeObject<JObject>(JsonConvert.SerializeObject(objErrorDetail));
            }

        }

    }
}

Introduction: In this article, we will explore how to implement dynamic dropdown lists in an ASP.NET MVC application. We'll use jQuery AJAX to fetch data from the server and populate dependent dropdown lists based on user selections. The provided code includes examples of how to create cascading dropdowns for countries, states, and cities, allowing users to select specific locations for student data.

Prerequisites: To follow this tutorial, you should have a basic understanding of ASP.NET MVC, C#, jQuery, and Entity Framework.

Building the Dropdown Form
Building the Dropdown Form: In the "Index.chtml" file, we have designed a form to collect student data, including cascading dropdowns for countries, states, and cities.
<!-- Index.chtml -->
<!-- ... (existing code) ... -->
<div class="text-light text-center my-3 d-flex justify-content-center gap-3">
    <div>
        @if (ViewBag.Country != null)
        {
            @Html.DropDownListFor(x => x.Country, ViewBag.Country as SelectList, "Select Country", new { @class = "form-control" })
        }
    </div>
    <div class="stateSection">
        <span id="states-loading-progress" style="display: none;">Please wait for State..</span>
        @Html.DropDownListFor(x => x.State, ViewBag.State as SelectList, "Select State", new { @class = "form-control" })
        @Html.ValidationMessageFor(x => x.State)
    </div>
    <div class="citySection">
        <span id="states-loading-progress" style="display: none;">Please wait for City..</span>
        @Html.DropDownListFor(x => x.City, ViewBag.City as SelectList, "Select City", new { @class = "form-control" })
        @Html.ValidationMessageFor(x => x.City)
    </div>
</div>
<!-- ... (existing code) ... -->

Implementing AJAX for Dropdowns
Implementing AJAX for Dropdowns: In the JavaScript section, we've added AJAX functions to handle the country and state dropdowns dynamically.
/*------ Country Function -------*/
$("#Country").change(function () {
    var stateID = $(this).val();
    $('#State').empty();
    $('#City').addClass('d-none');

    console.log(stateID);

    var statesProgress = $("#states-loading-progress");
    statesProgress.show();

    if (stateID > 0) {
        $(".stateSection").addClass('active');

        $.ajax({
            type: "GET",
            url: "/Home/GetStateById/" + stateID,
            success: function (data) {
                $("#State").html('');

                var defaultOption = "<option value>Select State</option>";
                $("#State").append(defaultOption);

                $.each(data, function (id, option) {
                    var optionHtml = "<option value=" + option.StateID + ">" + option.StateName + "</option>";
                    $("#State").append(optionHtml);
                });

                statesProgress.hide();
            },
            error: function (xhr, ajaxOptions, thrownError) {
                alert('State function failed');
                statesProgress.hide();
            }
        });
    } else {
        $(".stateSection").removeClass('active');
        $(".citySection").removeClass('active');
        $.notify("Please select a Country", "error");
    }
});


/*------ State Function -------*/
$("#State").change(function () {
    $('#City').removeClass('d-none');
    var cityID = $(this).val();
    var statesProgress = $("#states-loading-progress");
    statesProgress.show();

    if (cityID > 0) {
        $(".citySection").addClass('active');

        $.ajax({
            type: "GET",
            url: "/Home/GetCityById/" + cityID,
            success: function (data) {
                $("#City").html('');

                var defaultOption = "<option value>Select City</option>";
                $("#City").append(defaultOption);

                $.each(data, function (id, option) {
                    var optionHtml = "<option value=" + option.Id + ">" + option.CItyName + "</option>";
                    $("#City").append(optionHtml);
                });

                statesProgress.hide();
            },
            error: function (xhr, ajaxOptions, thrownError) {
                alert('City function failed');
                statesProgress.hide();
            }
        });
    } else {
        $(".citySection").removeClass('active');
        $.notify("Please select a State", "error");
    }
});

Handling Dropdown Requests in the Controller
Handling Dropdown Requests in the Controller: In the "HomeController," we've added action methods to retrieve country, state, and city data from the database and return them as JSON results for the AJAX requests.
// Home Controller Method
public class HomeController : Controller
{
    public ActionResult Index()
        {
            List<CountryTable> CountryList = db.CountryTable.ToList();
            ViewBag.Country = new SelectList(CountryList, "Id", "countryName");

            List<StateTable> StateList = db.StateTable.ToList();
            ViewBag.State = new SelectList(StateList, "StateID", "StateName");

            List<CityTable> CityList = db.CityTable.ToList();
            ViewBag.City = new SelectList(CityList, "Id", "CItyName");

            return View();
        }

        public JsonResult GetStateById(int ID)
        {
            db.Configuration.ProxyCreationEnabled = false;
            var stateList = db.StateTable.Where(x => x.CountryID == ID).ToList();
            return Json(stateList, JsonRequestBehavior.AllowGet);
        }

        public JsonResult GetCityById(int ID)
        {
            db.Configuration.ProxyCreationEnabled = false;
            var CityList = db.CityTable.Where(x => x.StateID == ID).ToList();
            return Json(CityList, JsonRequestBehavior.AllowGet);
        }

        public ActionResult EditStudent(int ID)
        {
            var result = repo.EditFunction(ID);
            // Set selected values for the dropdown lists
            List <CountryTable> CountryList = db.CountryTable.ToList();
            ViewBag.CountryList = new SelectList(CountryList, "Id", "countryName", result.Country);

            List<StateTable> StateList = db.StateTable.ToList();
            ViewBag.StateList = new SelectList(StateList, "StateID", "StateName", result.State);

            List<CityTable> CityList = db.CityTable.ToList();
            ViewBag.CityList = new SelectList(CityList, "Id", "CItyName", result.City);

            return View(result);
        }
    }
}

Conclusion: In this article, we have learned how to create dynamic dropdown lists with cascading behavior in an ASP.NET MVC application using AJAX. The JavaScript AJAX functions communicate with the server to fetch data based on user selections, and the ASP.NET MVC controller methods handle the requests and return JSON results. By following this guide, you can enhance your web application with more interactive features and improve the user experience with dynamic dropdowns. Happy coding!