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ASP.NET MVC Hosting - HostForLIFE.eu :: Using Ajax in MVC Application

clock June 21, 2016 00:16 by author Anthony

In asp.net web form application, if we need ajax service, we will need to create wcf services on server side to serve ajax calls, while in MVC web application, no wcf is needed, a controller will do.

Here are two examples (GET and POST) of how to use ajax in mvc application

Http Get example: ajax consumer in view

<script type="text/javascript">
  var user = {
                'id': 1
            };
    $.get(
                'home/getUser',
                user,
                function (data) {
                    alert(data.name);
                }
    );
</script>


Http Get example: ajax server in home controller

public class HomeController : Controller
{
    // data GET service
     public JsonResult getUser(int id)
     {
            User user = db.Users.where(u=>u.id==id)
            return Json(user,JsonRequestBehavior.AllowGet);     }
}

A few points:


Controller must return JsonResult rather than ActionResult as a normal controller does as we would want the data to be returnd as json data, and it does not have a ‘d’ wrapper

JsonRequestBehavior.AllowGet must be set in Json()call, otherwise you will get:

500 internal server error with message like

This request has been blocked because sensitive information could be disclosed to third party web sites when this is used in a GET request. To allow GET requests, set JsonRequestBehavior to AllowGet

You only need to set this parameter for GET and returning JSON array to avoid JSON hijacking, no need for POST requests.
Http POST example: ajax consumer in view


<script type="text/javascript">
var user={
            'name':’TheUser’,
            'age':30
        };
 $.post(
            'home/SaveUser',
            user,
            function (data) {
                if (data === true) {
                   alert('User is saved');
                }
                else {

                    alert('Failed to save the user');
                }
            },
            'json'
        );
</script>


Http POST example: ajax server in home controller

public class HomeController : Controller
{
    // data POST service
  [AcceptVerbs(HttpVerbs.Post)]
   public JsonResult SaveUser (string name, int age)
   {
        return Json(true);    }
}

A few points:

Have to decorate the controller with ‘POST’

Datatype in $.post in example is set to json, but it is not necessary to be so, if you just pass data in fields rather than in complex object. When it is not set to json it will use application/x-www-form-urlencoded as a way to pass data in standard post.


Summary:
In asp.net MVC you can use controller as ajax server without having to use wcf, compared with wcf, no configuration is needed

 

HostForLIFE.eu ASP.NET MVC Hosting
HostForLIFE.eu is European Windows Hosting Provider which focuses on Windows Platform only. We deliver on-demand hosting solutions including Shared hosting, Reseller Hosting, Cloud Hosting, Dedicated Servers, and IT as a Service for companies of all sizes. We have customers from around the globe, spread across every continent. We serve the hosting needs of the business and professional, government and nonprofit, entertainment and personal use market segments.



ASP.NET MVC Hosting - HostForLIFE.eu :: Configuring ELMAH In ASP.NET MVC

clock June 13, 2016 21:35 by author Anthony

In this article, I will integrate and setup ELMAH to asp.net MVC project. I will finish whole article in 5 different steps. ELMAH stands for Error Logging Modules and Handlers providing application wide error logging facilities. ELMAH is pluggable and easy to implement without changing single line of code. ELMAH work as interceptor of unhandled dotnet exceptions, that display over yellow screen of death. As per Author you can dynamically add ELMAH on running asp.net application without recompile or re-deploy whole application.You can download ELMAH binaries from google code or if you are using nuget then visit ELMAH nuget page.

Install

The best way to install any module to Asp.net MVC project is to use Nuget package Console. You can visit ELMAH nuget page for get latest version command.

Configure

After installing ELMAH , it will automatically update Web.Config file. If it's not so you can add following code to Web.Config file.

<configuration>
<configSections>
    <sectionGroup name="elmah">
      <section name="security" requirePermission="false" type="Elmah.SecuritySectionHandler, Elmah" />
      <section name="errorLog" requirePermission="false" type="Elmah.ErrorLogSectionHandler, Elmah" />
      <section name="errorMail" requirePermission="false" type="Elmah.ErrorMailSectionHandler, Elmah" />
      <section name="errorFilter" requirePermission="false" type="Elmah.ErrorFilterSectionHandler, Elmah" />
    </sectionGroup>
</configSections>

<system.web>   
    <httpModules>
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" />
      <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" />
      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" />
    </httpModules>
</system.web>

<system.webServer>
<modules>
      <add name="ErrorLog" type="Elmah.ErrorLogModule, Elmah" preCondition="managedHandler" />
      <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah" preCondition="managedHandler" />
      <add name="ErrorFilter" type="Elmah.ErrorFilterModule, Elmah" preCondition="managedHandler" />
</modules>
</system.webServer>
<elmah>
    <security allowRemoteAccess="false" />
    <errorLog type="Elmah.SqlErrorLog, Elmah" connectionStringName="YourConnectionStringName" />
</elmah>
    <location path="elmah.axd" inheritInChildApplications="false">
    <system.web>
      <httpHandlers>
        <add verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" />
      </httpHandlers>
      <!--
      <authorization>
        <allow roles="admin" />
        <deny users="*" /> 
      </authorization>
      --> 
    </system.web>
    <system.webServer>
      <handlers>
        <add name="ELMAH" verb="POST,GET,HEAD" path="elmah.axd" type="Elmah.ErrorLogPageFactory, Elmah" preCondition="integratedMode" />
      </handlers>
    </system.webServer>
  </location>
</configuration>
Usage Now, It's time to use and test elmah for application. Generate exception in Home Controller
public ActionResult Index()
{
   throw new Exception("This is test Exception");
          
   return View();
}


after generating exception check your elmah like http://www.example.com/elmah.axd
Here is our output

integrate-elmah-in-aspnet-mvc

integrate elmah in asp. net mvc

Security

In addition ELMAH provides seamless security feature to prevent unauthorized access. Please read our next article to make your elmah secure.

Filtering

ELMAH identify and store exceptions in different category, you can make or edit ELMAH error screen with different filters which we will discuss in our next ELMAH series.

Notification

You can setup ELMAH email notification when any exception occurs. To unable notification option you must include below code

Add ErrorMail module
<httpModules>
    <add name="ErrorMail" type="Elmah.ErrorMailModule, Elmah"/>
</httpModules>


Add SMTP Setting
<system.net>
    <mailSettings>
        <smtp deliveryMethod="network">
            <network host="..." port="25" userName="..." password="..." />
        </smtp>
    </mailSettings>
</system.net>
 

or
<elmah>
<errorMail from="..." to="..."  async="true" smtpServer="..." smtpPort="25" userName="..." password="..." />
</elmah>

 

 


HostForLIFE.eu ASP.NET MVC Hosting
HostForLIFE.eu is European Windows Hosting Provider which focuses on Windows Platform only. We deliver on-demand hosting solutions including Shared hosting, Reseller Hosting, Cloud Hosting, Dedicated Servers, and IT as a Service for companies of all sizes. We have customers from around the globe, spread across every continent. We serve the hosting needs of the business and professional, government and nonprofit, entertainment and personal use market segments.

 



ASP.NET MVC Hosting - HostForLIFE.eu :: How To Make Simple Application In ASP.NET MVC Using Select2?

clock June 6, 2016 23:46 by author Anthony

In this tutorial, I will show you how to make simple application in ASP.NET MVC using Select2. The infinite scrolling feature has also been implemented with server side options population. Select2 is very useful for dropdown lists with large datasets.

Why Select2 :

  • Using this jQuery plugin for dropdown lists, you can implement features such as option grouping, searching, infinite scrolling, tagging, remote data sets and other highly used features.
  • To use select2 in web projects, you just have to include JavaScript and CSS files of Select2 in your website.
  • Current version of select2 is 4.0.0. You can easily include these files by installation of NuGet package ‘Select2.js’ from NuGet package manager.

Steps of Implementation:
1. Create a blank ASP.NET MVC project, and install NuGet packages Select2.js, jQuery and jQuery Unobtrusive.
2. Add one controller with the name ‘HomeController’ and add view for default method ‘Index’.
3. Create new class in Models folder ‘IndexViewModel.cs as shown below:

public class IndexViewModel
{
   [Required(ErrorMessage="Please select any option")]
   public string OptionId { get; set; }
}

4. Bind ‘Index.cshtml’ view with IndexViewModelClass as model, by adding the following line in Index view:

@model Select2InMvcProject.Models.IndexViewModel

5. In ‘Index.cshtml’, include the css and js files below:

<link href="~/Content/css/select2.css" rel="stylesheet" />
<script src="~/Scripts/jquery-2.1.4.js"></script>
<script src="~/Scripts/select2.js"></script>
<script src="~/Scripts/jquery.validate.js"></script>
<script src="~/Scripts/jquery.validate.unobtrusive.js"></script>


6. Write the following code in the Index view for creation of select list:

@using (Html.BeginForm())
{
   <br /><br />
   @Html.DropDownListFor(n => n.OptionId, Enumerable.Empty<SelectListItem>(), new { @id = "txtOptionId", @style = "width:300px;" })
//Created selectlist with empty enumerable of SelectListItem and given //id as “txtOptionId”
   @Html.ValidationMessageFor(n => n.OptionId)
//Adds span of validation error message
   <br /><br />
<button type="submit">Submit</button>
   <br /><br />
}


7. For applying Select2 to the dropdown list created above, fetching data from server side and for infinite scroll, use the jQuery code below in Index view:

<script type="text/javascript">
   $(document).ready(function () {
       var pageSize = 20;
       var optionListUrl = '@Url.Action("GetOptionList", "Home")';
//Method which is to be called for populating options in dropdown //dynamically
       $('#txtOptionId').select2(
       {
           ajax: {
               delay: 150,
               url: optionListUrl,
               dataType: 'json',
               data: function (params) {
                   params.page = params.page || 1;
                   return {
                       searchTerm: params.term,
                       pageSize: pageSize,
                       pageNumber: params.page
                   };
               },
               processResults: function (data, params) {
                   params.page = params.page || 1;
                  return {
                       results: data.Results,
                       pagination: {
                           more: (params.page * pageSize) < data.Total
                       }
                   };
               }
           },
           placeholder: "-- Select --",
           minimumInputLength: 0,
           allowClear: true,
   });
});
</script>


8. Create new class in Models folder with name ‘Select2OptionModel’ and add the two classes below:

public class Select2OptionModel
{
       public string id { get; set; }
       public string text { get; set; }
}
public class Select2PagedResult
{
       public int Total { get; set; }
       public List<Select2OptionModel> Results { get; set; }
}


9. Create one new folder with name ‘Repository’ in the solution, and add new class in that folder with name ‘Select2Repository. The functions in this class are mentioned below:

public class Select2Repository
   {
       IQueryable<Select2OptionModel> AllOptionsList;
public Select2Repository()
{
           AllOptionsList = GetSelect2Options();
}
IQueryable<Select2OptionModel> GetSelect2Options()
                  {
                                     string cacheKey = "Select2Options";
                                     //check cache
                                     if (HttpContext.Current.Cache[cacheKey] != null)
                                     {
return (IQueryable<Select2OptionModel>)HttpContext.Current.Cache[cacheKey];
                                     }
                                     var optionList = new List<Select2OptionModel>();
                                     var optionText = "Option Number ";
                                     for (int i = 1; i < 1000; i++)
                                     {
                                     optionList.Add(new Select2OptionModel
                                     {
                                               id = i.ToString(),
                                               text = optionText + i
                                     });
                                   }
                                   var result = optionList.AsQueryable();
                                     //cache results
                                     HttpContext.Current.Cache[cacheKey] = result;
                                     return result;}
 
List<Select2OptionModel> GetPagedListOptions(string searchTerm, int pageSize, int pageNumber, out int totalSearchRecords)
                  {
                                     var allSearchedResults = GetAllSearchResults(searchTerm);
                                     totalSearchRecords = allSearchedResults.Count;
return allSearchedResults.Skip((pageNumber - 1) * pageSize).Take(pageSize).ToList();
                  }
                  List<Select2OptionModel> GetAllSearchResults(string searchTerm)
                  {

                                     var resultList = new List<Select2OptionModel>();
                                      if (!string.IsNullOrEmpty(searchTerm))
resultList = AllOptionsList.Where(n => n.text.ToLower().Contains(searchTerm.ToLower())).ToList();
                                     else
                                     resultList = AllOptionsList.ToList();
                                     return resultList;
                  }
                  public Select2PagedResult GetSelect2PagedResult(string searchTerm, int pageSize, int pageNumber)
                  {
                                     var select2pagedResult = new Select2PagedResult();
                                     var totalResults = 0;
                                     select2pagedResult.Results = GetPagedListOptions(searchTerm,
pageSize, pageNumber, out totalResults);
                                     select2pagedResult.Total = totalResults;
                                     return select2pagedResult;
}
}

10.  In HomeController class, create new method as shown below:

public JsonResult GetOptionList(string searchTerm, int pageSize, int pageNumber)
{
     var select2Repository = new Select2Repository();
     var result = select2Repository.GetSelect2PagedResult(searchTerm, pageSize, pageNumber);
     return Json(result, JsonRequestBehavior.AllowGet);
}

11. Once you are done with coding, you can build and run the project. The output will be shown as below:

dropdown1.png

dropdown2.png


HostForLIFE.eu ASP.NET MVC Hosting
HostForLIFE.eu is European Windows Hosting Provider which focuses on Windows Platform only. We deliver on-demand hosting solutions including Shared hosting, Reseller Hosting, Cloud Hosting, Dedicated Servers, and IT as a Service for companies of all sizes. We have customers from around the globe, spread across every continent. We serve the hosting needs of the business and professional, government and nonprofit, entertainment and personal use market segments.

 



European Cloud ASP.NET MVC Hosting - Spain :: Pipeline in ASP.NET MVC

clock April 22, 2014 09:49 by author Scott

In this article, I will write simple tutorial about detail pipeline of ASP.NET MVC.

Routing

Routing is the first step in ASP.NET MVC pipeline. typically, it is a pattern matching system that matches the incoming request to the registered URL patterns in the Route Table.

The UrlRoutingModule(System.Web.Routing.UrlRoutingModule) is a class which matches an incoming HTTP request to a registered route pattern in the RouteTable(System.Web.Routing.RouteTable).

When ASP.NET MVC application starts at first time, it registers one or more patterns to the RouteTable to tell the routing system what to do with any requests that match these patterns. An application has only one RouteTable and this is setup in the Application_Start event of Global.asax of the application.

public class RouteConfig
   {
   public static void RegisterRoutes(RouteCollection routes)
   {
   routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); 

   routes.MapRoute(
   name: "Default",
   url: "{controller}/{action}/{id}",
   defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional }
   );
   }
   }


protected void Application_Start()
{
   //Other code is removed for clarity
   RouteConfig.RegisterRoutes(RouteTable.Routes);
}

When the UrlRoutingModule finds a matching route within RouteCollection (RouteTable.Routes), it retrieves the IRouteHandler(System.Web.Mvc.IRouteHandler) instance(default is System.Web.MvcRouteHandler) for that route. From the route handler, the module gets an IHttpHandler(System.Web.IHttpHandler) instance(default is System.Web.MvcHandler).

public interface IrouteHandler
{
   IHttpHandler GetHttpHandler(RequestContext requestContext);
}

Controller Initialization

The MvcHandler initiates the real processing inside ASP.NET MVC pipeline by using ProcessRequest method. This method uses the IControllerFactory instance (default is System.Web.Mvc.DefaultControllerFactory) to create corresponding controller.

protected internal virtual void ProcessRequest(HttpContextBase httpContext)
{
   SecurityUtil.ProcessInApplicationTrust(delegate {
   IController controller;
   IControllerFactory factory;
   this.ProcessRequestInit(httpContext, out controller, out factory);
   try
   {
   controller.Execute(this.RequestContext);
   }
   finally
   {
   factory.ReleaseController(controller);
   }
   });
}

Action Execution

1. When the controller is initialized, the controller calls its own InvokeAction() method by passing the details of the chosen action method. This is handled by the IActionInvoker.

public virtual bool InvokeAction(ControllerContext controllerContext, string actionName)

2. After chosen of appropriate action method, model binders(default is System.Web.Mvc.DefaultModelBinder) retrieves the data from incoming HTTP request and do the data type conversion, data validation such as required or date format etc. and also take care of input values mapping to that action method parameters.

3. Authentication Filter was introduced with ASP.NET MVC5 that run prior to authorization filter. It is used to authenticate a user. Authentication filter process user credentials in the request and provide a corresponding principal. Prior to ASP.NET MVC5, you use authorization filter for authentication and authorization to a user.

By default, Authenticate attribute is used to perform Authentication. You can easily create your own custom authentication filter by implementing IAuthenticationFilter.

4. Authorization filter allow you to perform authorization process for an authenticated user. For example, Role based authorization for users to access resources.

By default, Authorize attribute is used to perform authorization. You can also make your own custom authorization filter by implementing IAuthorizationFilter.

5. Action filters are executed before(OnActionExecuting) and after(OnActionExecuted) an action is executed. IActionFilter interface provides you two methods OnActionExecuting and OnActionExecuted methods which will be executed before and after an action gets executed respectively. You can also make your own custom ActionFilters filter by implementing IActionFilter.

6. When action is executed, it process the user inputs with the help of model (Business Model or Data Model) and prepare Action Result.

Result Execution

1. Result filters are executed before(OnResultnExecuting) and after(OnResultExecuted) the ActionResult is executed. IResultFilter interface provides you two methods OnResultExecuting and OnResultExecuted methods which will be executed before and after an ActionResult gets executed respectively. You can also make your own custom ResultFilters filter by implementing IResultFilter.

2. Action Result is prepared by performing operations on user inputs with the help of BAL or DAL. The Action Result type can be ViewResult, PartialViewResult, RedirectToRouteResult, RedirectResult, ContentResult, JsonResult, FileResult and EmptyResult.

3. Various Result type provided by the ASP.NET MVC can be categorized into two category- ViewResult type and NonViewResult type. The Result type which renders and returns an HTML page to the browser, falls into ViewResult category and other result type which returns only data either in text format, binary format or a JSON format, falls into NonViewResult category.

View Initialization and Rendering

1. ViewResult type i.e. view and partial view are represented by IView(System.Web.Mvc.IView) interface and rendered by the appropriate View Engine.

public interface Iview
{
  
void Render(ViewContext viewContext, TextWriter writer);
}

2. This process is handled by IViewEngine(System.Web.Mvc.IViewEngine) interface of the view engine. By default ASP.NET MVC provides WebForm and Razor view engines. You can also create your custom engine by using IViewEngine interface and can registered your custom view engine in to your Asp.Net MVC application as shown below:

protected void Application_Start()
{
  
//Remove All View Engine including Webform and Razor
   ViewEngines.Engines.Clear();
   //Register Your Custom View Engine
   ViewEngines.Engines.Add(new CustomViewEngine());
   //Other code is removed for clarity
}

3. Html Helpers are used to write input fields, create links based on the routes, AJAX-enabled forms, links and much more. Html Helpers are extension methods of the HtmlHelper class and can be further extended very easily. In more complex scenario, it might render a form with client side validation with the help of JavaScript or jQuery.



About HostForLIFE.eu

HostForLIFE.eu is European Windows Hosting Provider which focuses on Windows Platform only. We deliver on-demand hosting solutions including Shared hosting, Reseller Hosting, Cloud Hosting, Dedicated Servers, and IT as a Service for companies of all sizes.

We have offered the latest Windows 2012 Hosting, ASP.NET 4.5 Hosting, ASP.NET MVC 5 Hosting, and SQL 2014 Hosting.


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