title: How can I parse query string in WPF?
body: <p>hi I have wpf application. I created a pop up that act as container of pages being called.
  the pop up has frame in which I just assign source for it to load. My prob is that I need to pass a query so I can retrieve it upon loading of the called page.</p>
  
  <p>I have looked in google and most of the answers are saying use NavigationService.Navigate.CurrentSource.Query but the prob is Navigation is null when I use it. </p>
  
  <p>activity flow:
  When btn clicked = it calls window pop up show with some parameters.
  pop up loads : selects which case to do according to passed param (see below). In the code below I want to pass the value  x as query. </p>
  
  <p>My code:</p>
  
  <pre><code> case PopUpModule.GALContinuingEduHistory:
                  string x = "hello";
                  lblHeader.Text = "GAL Continuing Education History";
                  frmContent.Source = new Uri ("../Forms/FileMaintenance/Mediator/ContinuingEducHistoryPopUp.xaml?value=x",           UriKind.RelativeOrAbsolute);
                  break;
  </code></pre>
  
  <p>Now my prob is how do I parse it when ContinuingEducHistoryPopUp.xaml loads? </p>
  
  <p>thanks</p>