Q:

How to use QueryString

How can I have different URL ids like www.somewebsite.com/index?theidentifier=34 only in ASP.NET MVC not Webforms.

A:

Well, for what purpose?  Just to access the value?  All querystring values can be routed to params in the action method like:
public ActionResult index(int? theidentifier)
{
   //process value
}

Or, you can use the QueryString collection as mentioned above, I think it's via this.RequestContext.HttpContext.Request.QueryString.

