component-development

name: component-development description: "Provides a step-by-step workflow for creating Blazor components that emulate ASP.NET Web Forms controls in the BlazorWebFormsComponents library. Covers base class selection (BaseWebFormsComponent, BaseStyledComponent, DataBoundComponent, BaseValidator), Web Forms property and event naming conventions, Playwright integration testing setup, and the complete checklist from component creation through documentation and navigation updates. Use when implementing a new BWFC component, choosing the correct base class for a control type, adding unit or integration tests, or extending an existing component with new Web Forms property support."

Component Development Skill

This skill covers creating new Blazor components that emulate ASP.NET Web Forms controls.

Related Guides

• HTML Output Matching Guide - How to ensure Blazor components render identical HTML to Web Forms controls

Quick Reference

Creating a New Component

1. Identify the Web Forms control from System.Web.UI.WebControls
2. Research the HTML output using the HTML Output Matching Guide
3. Create component files:
   • src/BlazorWebFormsComponents/{ComponentName}.razor
   • src/BlazorWebFormsComponents/{ComponentName}.razor.cs
4. Inherit from appropriate base class:
   • BaseWebFormsComponent - Basic components
   • BaseStyledComponent - Components with styling
   • DataBoundComponent<T> - Data-bound components
5. Add unit tests in src/BlazorWebFormsComponents.Test/{ComponentName}/
6. Add sample page in samples/AfterBlazorServerSide/Components/Pages/ControlSamples/{ComponentName}/
7. Add integration tests using Playwright in samples/AfterBlazorServerSide.Tests/
8. Create documentation in docs/{Category}/{ComponentName}.md
9. Update navigation:
   • Add to samples/AfterBlazorServerSide/Components/Layout/NavMenu.razor (TreeView)
   • Add to samples/AfterBlazorServerSide/Components/Pages/ComponentList.razor (home page catalog)
   • Update mkdocs.yml and README.md

Base Class Selection

Property Naming Convention

Match Web Forms property names exactly:

• Text not Label or Content
• CssClass not Class or ClassName
• NavigateUrl not Href or Url
• ImageUrl not Src or Source

Event Naming Convention

Prefix with On:

• OnClick for click events
• OnCommand for command events
• OnSelectedIndexChanged for selection changes
• OnDataBinding for data binding events

Integration Testing Requirements

Every component must have integration tests in samples/AfterBlazorServerSide.Tests/ using Playwright:

1. Page load test in ControlSampleTests.cs:

   • Add route to the appropriate [Theory] test (EditorControl, DataControl, etc.)
   • Verifies page loads without console errors or page errors

2. Interactive test in InteractiveComponentTests.cs (for interactive components):

   • Test user interactions (clicks, input, selection changes)
   • Verify component responds correctly to user actions
   • Assert no console errors during interaction

Example page load test entry:

[Theory]
[InlineData("/ControlSamples/YourComponent")]
public async Task EditorControl_Loads_WithoutErrors(string path)

Example interactive test:

[Fact]
public async Task YourComponent_Interaction_Works()
{
    var page = await _fixture.NewPageAsync();
    try
    {
        await page.GotoAsync($"{_fixture.BaseUrl}/ControlSamples/YourComponent");
        // Test interactions...
        // Assert expected behavior...
    }
    finally
    {
        await page.CloseAsync();
    }
}

Run integration tests with:

dotnet test samples/AfterBlazorServerSide.Tests