title: Debugger always Break when invoke GetFileAsync in windows 8 store apps (metro style)
body: <p>This problem confuse me several days, when the code run to </p>
  
  <pre><code>await ApplicationData.Current.LocalFolder.GetFileAsync(udFileName);
  </code></pre>
  
  <p>The app was always jump to</p>
  
  <pre><code>UnhandledException += (sender, e) =&gt;
          {
              if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break();
          };
  </code></pre>
  
  <p>The Exception e is：</p>
  
  <pre><code>{Windows.UI.Xaml.UnhandledExceptionEventArgs}
  Exception   {"Object reference not set to an instance of an object."}   
  System.Exception {System.NullReferenceException}
  Message "System.NullReferenceException.......
  </code></pre>
  
  <p>Following is the function I invoked:</p>
  
  <pre><code>public async void RestoreUserDefaults()
      {
          string udFileName = "userdefaults.udef";
          bool bExist = true;
          {
              try
              {
                  await ApplicationData.Current.LocalFolder.GetFileAsync(udFileName);
              }
              catch (FileNotFoundException)
              {
                  bExist = false;
              }
          }
      }
  </code></pre>
  
  <p>I had add the file type to the package.appxmanifest.</p>
  
  <p>anyone can help me, so many thanks.....</p>