Request Migration

This sample demonstrates the RequestShim that provides Web Forms-compatible Request.QueryString, Request.Url, and Request.Cookies access in Blazor. The shim falls back to NavigationManager when HttpContext is unavailable (interactive mode).

1. Request.QueryString

Access query string parameters using the same dictionary-style syntax as Web Forms. The shim falls back to parsing from NavigationManager.Uri in interactive mode.

string name = Request.QueryString["name"];
string id = Request.QueryString["id"];

// Same code works!
string name = Request.QueryString["name"];
string id = Request.QueryString["id"];

2. Request.Url

Access the full request URL. Falls back to NavigationManager.Uri in interactive mode.

3. Request.Cookies (with SSR Guard)

Cookies require HttpContext and are only available during SSR/pre-render. In interactive mode, Request.Cookies returns an empty collection. Use the IsHttpContextAvailable guard pattern.

string theme = Request.Cookies["theme"]?.Value;

// Guard for HttpContext availability
if (IsHttpContextAvailable)
{
    var theme = Request.Cookies["theme"];
}