render-info

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Using the RendererInfo class in Blazor to detect rendering context and interactivity.

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[Code Generation]

When & Why to Use This Skill

This Claude skill provides expert guidance on utilizing the RendererInfo class in Blazor (.NET 8+) to detect rendering contexts and interactivity states. It enables developers to write smarter components that adapt their behavior based on whether they are running in Static SSR, Interactive Server, WebAssembly, or Hybrid environments, ensuring a seamless user experience and robust UI logic.

Use Cases

  • Preventing broken user interactions by disabling buttons and input fields during the static prerendering phase until the interactive runtime is fully active.
  • Implementing environment-aware UI logic by identifying the specific rendering platform, such as displaying different components for WebAssembly versus Blazor Hybrid (MAUI/WPF).
  • Optimizing initial page load and SEO by serving lightweight static HTML forms during server-side rendering and swapping them for rich interactive components once the client-side circuit is established.
namerender-info
descriptionUsing the RendererInfo class in Blazor to detect rendering context and interactivity.

Using RendererInfo in Blazor

The RendererInfo class in Blazor provides runtime information about the renderer that is executing the component. It is particularly useful for detecting whether a component is running interactively or statically, and for identifying the specific rendering platform (e.g., Server, WebAssembly, WebView).

Key Properties

IsInteractive

  • Type: bool
  • Description: Indicates whether the component is currently running in an interactive render mode.
  • Usage: Use this to conditionally render UI elements that require interactivity, such as disabling buttons or showing loading indicators during static server-side rendering (SSR) or prerendering.
@if (!RendererInfo.IsInteractive)
{
    <p>Connecting...</p>
}
else
{
    <button @onclick="HandleClick">Click Me</button>
}

Name

  • Type: string
  • Description: Returns the name of the renderer.
  • Common Values:
    • "Static": Running in static server-side rendering (SSR).
    • "Server": Running in Interactive Server mode (SignalR).
    • "WebAssembly": Running in Interactive WebAssembly mode.
    • "WebView": Running in a Blazor Hybrid application (MAUI, WPF, WinForms).
<p>Current Render Mode: @RendererInfo.Name</p>

Common Scenarios

1. Disabling Inputs During Prerendering

When a component is prerendered on the server, event handlers (like @onclick) are not active. You can use RendererInfo.IsInteractive to disable inputs until the interactive runtime takes over.

<button @onclick="Submit" disabled="@(!RendererInfo.IsInteractive)">
    Submit
</button>

2. Rendering Different Content for Static vs. Interactive

You might want to show a simple HTML form for static SSR and a rich, interactive component for interactive modes.

@if (RendererInfo.Name == "Static")
{
    <form action="/search" method="get">
        <input name="q" />
        <button type="submit">Search</button>
    </form>
}
else
{
    <SearchComponent />
}
  • AssignedRenderMode: A property on ComponentBase that tells you which render mode was assigned to the component (e.g., InteractiveServer, InteractiveWebAssembly, InteractiveAuto). Note that AssignedRenderMode might be null during static rendering.

Important Notes

  • RendererInfo is available in .NET 8.0 and later.
  • It is a static class, so you can access it directly in your Razor markup or C# code without injection.