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.

csharp
@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).

csharp
<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.

razor
<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.

razor
@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.