Agent Skills: Using RendererInfo in Blazor

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 />
}

Related Concepts

• 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.