如何在 UWP 中的“Enter”上关闭 ContentDialog

Question

I've been trying to get a simple ContentDialog with a TextBox to close when the user hits Enter while still in the TextBox . Sadly it doesn't even work without a TextBox , even though the ContentDialog responds to Esc .

I was hoping there was a way to set a Result from inside the KeyDown Handler of the TextBox , but it seems ContentDialog lacks this?!

Answer 1

You can close the ContentDialog using Hide() method in TextBox KeyDown handler, simple example:

ContentDialog c = new ContentDialog();

var tb = new TextBox();

tb.KeyDown += (sender, args) =>
{
     if (args.Key == VirtualKey.Enter)
     {
          c.Hide();
     }
};

c.Content = tb;
c.ShowAsync();

EDIT: But it seems to be more complicated when you want to close the dialog without TextBox . You have to subscribe on global Window.Current.CoreWindow.KeyDown event:

ContentDialog c = new ContentDialog();

Window.Current.CoreWindow.KeyDown += (sender, args) =>
{
      if (args.VirtualKey == VirtualKey.Enter)
      {
            c.Hide();
      }
};
c.ShowAsync();

Answer 2

Here is my final solution that would get me a ContentDialogResult.Primary on Enter

I added this to my ContentDialog:

    public new IAsyncOperation<ContentDialogResult> ShowAsync()
    {
        var tcs = new TaskCompletionSource<ContentDialogResult>();

        CaptionTB.KeyDown += (sender, args) =>
        {
            if (args.Key != VirtualKey.Enter) return;
            tcs.TrySetResult(ContentDialogResult.Primary);
            Hide();
            args.Handled=true;
        };

        var asyncOperation = base.ShowAsync();
        asyncOperation.AsTask().ContinueWith(task => tcs.TrySetResult(task.Result));
        return tcs.Task.AsAsyncOperation();
    }

unfortunately ShowAsync isn't virtual so I had to new the function. It works well for me though!

Answer 3

The short answer is that it isn't (cleanly) possible without workarounds and hacks that will preserve the functionality of identifying which button was pressed. The long answer is that it's fortunately very clean and easy to subclass ContentDialog to do exactly what we want:

using System;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Input;

namespace NeoSmart.Dialogs
{
    class HotkeyContentDialog : ContentDialog
    {
        public new event TypedEventHandler<ContentDialog, ContentDialogButtonClickEventArgs> PrimaryButtonClick;
        public new event TypedEventHandler<ContentDialog, ContentDialogButtonClickEventArgs> SecondaryButtonClick;

        public ContentDialogResult Result { get; set; }
        public new async Task<ContentDialogResult> ShowAsync()
        {
            var baseResult = await base.ShowAsync();
            if (baseResult == ContentDialogResult.None)
            {
                return Result;
            }
            return baseResult;
        }

        protected override void OnKeyUp(KeyRoutedEventArgs e)
        {
            if (e.Key == Windows.System.VirtualKey.Enter)
            {
                Result = ContentDialogResult.Primary;
                PrimaryButtonClick?.Invoke(this, default(ContentDialogButtonClickEventArgs));
                Hide();
            }
            else if (e.Key == Windows.System.VirtualKey.Escape)
            {
                Result = ContentDialogResult.Secondary;
                SecondaryButtonClick?.Invoke(this, default(ContentDialogButtonClickEventArgs));
                Hide();
            }
            else
            {
                base.OnKeyUp(e);
            }
        }
    }
}

Just use HotkeyContentDialog instead of ContentDialog and all will be well.

Answer 4

It has been a while since this question has been asked, but a ContentDialog has a DefaultButton property that handles Enter in the way you want.

ContentDialog.DefaultButton

For a TextBox, I assume you have to set the AcceptsReturn property to false because this may interfere with the Enter that is intended to close the dialog.

TextBox.AcceptsReturn

Answer 5

Mahmouds solution is more than perfect! Should be accepted as answer IMO. Here is the further reworked HotkeyContentDialog class from me:

public class HotkeyContentDialog : ContentDialog
{
    public new event TypedEventHandler<ContentDialog, ContentDialogButtonClickEventArgs> PrimaryButtonClick;
    public new event TypedEventHandler<ContentDialog, ContentDialogButtonClickEventArgs> SecondaryButtonClick;
    public ContentDialogResult Result { get; set; }

    public new async Task<ContentDialogResult> ShowAsync()
    {
        var baseResult = await base.ShowAsync();
        return baseResult == ContentDialogResult.None ? Result : baseResult;
    }

    protected override void OnKeyUp(KeyRoutedEventArgs e)
    {
        switch (e.Key)
        {
            case Windows.System.VirtualKey.Enter:
                Result = ContentDialogResult.Primary;
                PrimaryButtonClick?.Invoke(this, default);
                Hide();
                break;
            case Windows.System.VirtualKey.Escape:
                Result = ContentDialogResult.Secondary;
                SecondaryButtonClick?.Invoke(this, default);
                Hide();
                break;
            default:
                base.OnKeyUp(e);
                break;
        }
    }
}