title: Got exception in file picker c# and XAML if choose nothing?
body: <p>I have problem with my App i made choose button to select file from PC but i got exception if i didn't choose any files 
  hope anyone can help 
  thanks <img src="https://i.stack.imgur.com/UXXMR.png" alt="enter image description here"></p>
  
  <p>Edit: Code with Try/Catch blocks</p>
  
  <pre><code>openPicker.FileTypeFilter.Add(".wmv");
  openPicker.FileTypeFilter.Add(".mp4"); 
  openPicker.FileTypeFilter.Add(".wma"); 
  openPicker.FileTypeFilter.Add(".mp3"); 
  StorageFile file = await openPicker.PickSingleFileAsync(); 
  var stream = (dynamic)null; 
  try { 
        stream = await file.OpenAsync(Windows.Storage.FileAccessMode.Read);
  } catch (Exception ex) { 
      Frame.Navigate(typeof(music)); // optional to back to choose page 
   }
  </code></pre>