How can I tell if Request/Response is available in Application_Error?

Question

If Application_Error is triggered by an exception in the application start up i.e. RouteConfigor BundleConfig how can you check if the Request/Response is available? Currently the call to Response.Clear throws System.Web.HttpException with additional information Response is not available in this context.

void Application_Error(object sender, EventArgs e)
{
    //Log error
    Log.Error(e);

    //Clear
    Response.Clear();
    Server.ClearError();

    //Redirect
    Response.Redirect("~/Error");
}

Other questions suggest rewriting to not use Response or to use HttpContext.Current.Response or changing IIS config.

In summary; how can I tell if the error has occurred during app start?

Answer 1

You want to check whether it is HttpException.

protected void Application_Error(Object sender, EventArgs e)
{
    var exception = Server.GetLastError();

    // Log error
    LogException(exception);

    var httpException = exception as HttpException;
    if (httpException != null)
    {
        Response.Clear();
        Server.ClearError();
        Response.TrySkipIisCustomErrors = true;

        Response.Redirect("~/Error");
    }
}