How to get TextBox to only accept numbers?

I looked around for ages but couldn’t find anything on this. I tried setting up validation (which is also very undocumented), but still have issues with that.

My TextBox is supposed to only accept unsigned integers. I think there should be some easy property to set to TextBox to define what types of inputs it can accept. (Android has this)

I tried

public uint? AppId {
get => _appId;
set
  {
    if(!(value is uint?))
    {
      throw new DataValidationException("Invalid Steam App Id");
    }

    _appId = value;
  }
}

which I got from #4845, but the problem is that the program still closes with System.ArgumentException: 'f is not a valid value for UInt32. (Parameter 'value')', since the property itself doesn’t accept strings.

[maxkatz6]

@SpyceTewan as mentioned above, you can use Converter or Behaviors.

Although I would be nice to have UWP InputScope alternative (possible values - link). With that this issue could be solved simply <TextBox InputScrope="Number" /> But I believe this feature should be planned and introduced only with IME and mobile in mind @kekekeks.

[Dorin-Foaltin]

@StefanH-AT: have you managed to fully restrict input of invalid characters, like letters (eg: ‘a’ or ‘b’)?

I’m trying to allow only entering of numbers, and it seems like this should work, but for me it only works after the app is minimized + restored, forcing a redraw.

I’ve tried calling InvalidateVisual()/ other methods after KeyDown/ KeyUp/ ValueChanghed, but this doesn’t really fix it, so I was thinking maybe you have a work around for it?

In this gif below, see that I can enter letters, these are not cleared until I minimize and restore the app: