Both appear to be comparable at first glance. They enable us to reuse user interface elements on other sites. However, they differ greatly under the hood. The distinctions, applications, performance factors, and when to pick one over the other will all be covered in this article.

What is a Partial View?

• A Partial View is a Razor view (.cshtml) file that can be reused inside other views.
• It is essentially a fragment of HTML + Razor that does not have its own controller logic.

Think of it like a shared template. If you’ve worked with ASP.NET WebForms before, you can compare it to a UserControl (.ascx).
Example

_LoginPartial.cshtml
@if (User.Identity.IsAuthenticated)
{
    <p>Welcome, @User.Identity.Name</p>
    <a href="/Account/Logout">Logout</a>
}
else
{
    <a href="/Account/Login">Login</a>
}

You can include it in your main view as:
@Html.Partial("_LoginPartial")

or asynchronously:

@await Html.PartialAsync("_LoginPartial")
Key Point: A Partial View does not have its own logic. It depends on the data passed from the parent view’s controller.

What is a ViewComponent?
A ViewComponent is like a mini-controller.
It combines C# logic + a Razor view into a self-contained unit.

It allows you to encapsulate business logic and rendering in one place, making it perfect for widgets that require their own data fetching.

Example
ViewComponents/CartSummaryViewComponent.cs
public class CartSummaryViewComponent : ViewComponent
{
    private readonly ICartService _cartService;

    public CartSummaryViewComponent(ICartService cartService)
    {
        _cartService = cartService;
    }

    public IViewComponentResult Invoke()
    {
        var cart = _cartService.GetCart(User.Identity.Name);
        return View(cart);
    }
}

The Razor view (Views/Shared/Components/CartSummary/Default.cshtml):
<div class="cart-summary">
    <p>Items in cart: @Model.Items.Count</p>
    <p>Total: @Model.TotalPrice.ToString("C")</p>
</div>

Usage in your main view:
@await Component.InvokeAsync("CartSummary")

Key Point: A ViewComponent has its own logic and data source. It does not rely on the parent controller’s model.

Key Differences Between Partial View and ViewComponent

When to Use Partial View?

Use a Partial View when:

• You only need reusable HTML markup.
• Data comes from the parent controller.
• Example scenarios:
• Website header and footer
• Navigation menus
• Shared static templates like the Terms & Conditions section

Code Example

@Html.Partial("_Header")
@Html.Partial("_Footer")

When to Use ViewComponent?
Use a ViewComponent when:

• You need business logic + view rendering together.
• Data comes from a different source than the parent view.
• You want testability (since ViewComponents can be unit tested).
• Example scenarios:
  • Shopping cart summary
  • Latest blog posts widget
  • Notification panel
  • User profile box

Code Example
@await Component.InvokeAsync("LatestPosts", new { count = 5 })

Performance Considerations

• Partial View is faster for simple static rendering because it does not invoke additional logic.
• ViewComponent is slightly heavier, but it provides better separation of concerns and testability.
• In real-world projects, mixing both approaches works best.

Conclusion
ASP.NET MVC/Core offers two strong tools for creating modular, maintainable applications: Partial Views and ViewComponents.

• For basic, static UI fragments, use partial views.
• For reusable, logic-driven user interface elements, use ViewComponents.

You may improve the scalability, maintainability, and cleanliness of your application by selecting the appropriate strategy for each situation.