Migrating from .NET Web Forms to Blazor: A Step-by-Step Guide - Migrating Controls

Migrate your .NET Web Forms app to Blazor using our step-by-step guide for converting controls to components.


Steven Lieberman

1/2/20243 min read

a woman with a white dress and a blue sky
a woman with a white dress and a blue sky

Are you considering migrating your .NET Web Forms application to Blazor? Blazor, a new web framework by Microsoft, allows you to build interactive web UIs using C# instead of JavaScript. It offers a modern and more maintainable approach to web development. One of the critical aspects of migrating from Web Forms to Blazor is migrating controls. In this step-by-step guide, we'll explore how to migrate your WebForms controls to Blazor components.

Understanding the Difference: Server Controls vs. Components

Before we dive into the migration process, let's understand the fundamental difference between server controls in Web Forms and components in Blazor.

In Web Forms, server controls are HTML-like elements that run on the server and generate HTML markup for the client. They encapsulate both the UI and the logic associated with it. In contrast, Blazor components are self-contained units of UI with associated logic written in C#. They are rendered on the client side and can communicate with the server through APIs.

Migrating WebForms Controls to Blazor Components

Now that we understand the difference between server controls and components, let's explore the step-by-step process of migrating your WebForms controls to Blazor components.

Step 1: Identify the Controls to Migrate

The first step is to identify the WebForms controls that need to be migrated. Inventory all the controls used in your application and categorize them based on their functionality.

For example, if you have a GridView control in Web Forms, you can consider migrating it to a Blazor DataGrid component. Similarly, a TextBox control can be migrated to a Blazor InputText component.

Step 2: Create Blazor Components

Once you have identified the controls to migrate, create corresponding Blazor components for each control. Blazor components are C# classes that inherit from the ComponentBase class. They have a Render method where you define the UI markup and associated logic.

For example, if you have a GridView control, create a Blazor DataGrid component. In the Render method, define the HTML markup and logic to render the grid.

Step 3: Migrate Control Properties and Events

Next, you'll need to migrate the properties and events of your WebForms controls to their respective Blazor components. In Web Forms, controls have properties like Text and Visible and events like Click and TextChanged.

In Blazor, you can create properties in your components to represent the state of the control. For example, if you have a TextBox control with a Text property, create a corresponding property in your Blazor InputText component.

Similarly, for events, you can define event callbacks in your Blazor components and raise them when the corresponding action occurs. For example, if you have a button with a Click event, create a corresponding event callback in your Blazor Button component.

Step 4: Handle Control Lifecycle

Web Forms controls have a well-defined lifecycle with events like Page_Load and PreRender. In Blazor, you'll need to handle the lifecycle of your components differently.

Blazor components have lifecycle methods like OnInit, OnAfterRender, and Dispose. You can override these methods in your components to perform initialization, cleanup, and other operations.

Step 5: Update UI Markup

Web Forms controls generate HTML markup on the server and send it to the client. Blazor defines the UI markup within the component using HTML-like syntax.

Update the UI markup in your Blazor components to match the design and functionality of your WebForms controls. Use Blazor's syntax for data binding, conditional rendering, and other UI operations.

Step 6: Test and Debug

Once you have migrated your controls to Blazor components, testing and debugging your application thoroughly is essential. Test each control's functionality and ensure the UI and logic work as expected.

Use Blazor's debugging and browser developer tools to identify and fix any issues. Pay attention to any JavaScript interop or server communication required for your components.

Step 7: Gradually Replace Web Forms Pages

Finally, as you migrate your controls to Blazor components, you can replace your Web Forms pages with Blazor pages. Gradually refactor your application to use Blazor components for new features and progressively replace existing Web Forms pages with Blazor pages.

Take a phased approach to ensure a smooth transition and minimize user disruption. Monitor performance and user feedback during the migration process.


Migrating from .NET Web Forms to Blazor is an exciting journey that opens up new possibilities for modern web development. By migrating your WebForms controls to Blazor components, you can leverage the power of C# and enjoy a more maintainable and interactive web UI.

Remember to identify the controls to migrate, create corresponding Blazor components, migrate control properties and events, handle the control lifecycle, update UI markup, and thoroughly test and debug your application. Gradually replace Web Forms pages with Blazor pages to complete the migration process.

With this step-by-step guide, you're well-equipped to embark on your migration journey and unlock the full potential of Blazor.