How to use querystring in following code?

See more:

C#

ASP.NET

SQL

firstpage.aspx :

Response.Redirect("branch?uid="+DUserName);

secondpage.aspx :

uname = Request.QueryString[0];


global.asax.cs :

void Application_Start(object sender, EventArgs e)
      {
          RoutingData(RouteTable.Routes);
      }

      private void RoutingData(RouteCollection routecollection)
      {
          routecollection.MapPageRoute("Student", "Student/Profile", "~/View/StudentProfile.aspx");

}

I have used global.asax.cs to redirect to the another page. Please tell me how can I use query string?