CODEWITHSUNDEEP
windows-store-appswin-universal-app
Maxime Labelle
Maxime Labelle

Reputation: 3639

Does the MessageDialog class for UWP Apps support three buttons on Mobile?

I'm creating a simple program for reading text file on the Windows Phone. I decided to make it a Universal Windows Platform (UWP) App.

In the app, I have a very simple MessageDialog, with three options, Yes, No, Cancel. It works perfectly on the Desktop and in the Simulator. However, when testing with the actual device, the ShowAsync method fails with the message: "Value does not fall in the expected range".

This only happens if there are more than two commands registered in the dialog. Does the MessageDialog class really supports up to three commands - as the documentation suggests - or is this only applying for UWP Apps running on Desktop devices?

Upvotes: 4

Views: 1500

Answers (2)

Yury Schkatula
Yury Schkatula

Reputation: 5369

At the moment, there is a clear statement in the docs:

The dialog has a command bar that can support up to 3 commands in desktop apps, or 2 commands in mobile apps.

Sad but true: on mobiles, there are two commands only. Need more? Use ContentDialog instead.

Upvotes: 0

Peter Torr
Peter Torr

Reputation: 12019

It looks like the documentation is missing information about Mobile (and really the API should do a better job here).

For Mobile, if you hit the Back key you get a null return value, so you can do this (not recommended coding pattern, but best I can think of):

async Task Test()
{
  const int YES = 1;
  const int NO = 2;
  const int CANCEL = 3;

  var dialog = new MessageDialog("test");
  dialog.Commands.Add(new UICommand { Label = "yes", Id = YES });
  dialog.Commands.Add(new UICommand { Label = "no", Id = NO });

  // Ugly hack; not really how it's supposed to be used.
  // TODO: Revisit if MessageDialog API is updated in future release
  var deviceFamily = AnalyticsInfo.VersionInfo.DeviceFamily;
  if (deviceFamily.Contains("Desktop"))
  {
    dialog.Commands.Add(new UICommand { Label = "cancel", Id = CANCEL });
  }
  // Maybe Xbox 'B' button works, but I don't know so best to not do anything
  else if (!deviceFamily.Contains("Mobile"))
  {
    throw new Exception("Don't know how to show dialog for device "
      + deviceFamily);
  }

  // Will return null if you press Back on Mobile
  var result = await dialog.ShowAsync();

  // C# 6 syntactic sugar to avoid some null checks
  var id = (int)(result?.Id ?? CANCEL);

  Debug.WriteLine("You chose {0}", id);
}

Upvotes: 0

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