Interpret enter as tab WPF

Question

I want to interpret Enter key as Tab key in whole my WPF application, that is, everywhere in my application when user press Enter I want to focus the next focusable control,except when button is focused. Is there any way to do that in application life circle? Can anyone give me an example?
Thanks a lot!

Answer 1

You can use my EnterKeyTraversal attached property code if you like. Add it to the top-level container on a WPF window and everything inside will treat enter as tab:

<StackPanel my:EnterKeyTraversal.IsEnabled="True">
    ...
</StackPanel>

Answer 2

Based on Richard Aguirre's answer, which is better than the selected answer for ease of use, imho, you can make this more generic by simply changing the Grid to a UIElement.

To change it in whole project you need to do this

• In App.xaml.cs:

   protected override void OnStartup(StartupEventArgs e)
   {           
       EventManager.RegisterClassHandler(typeof(UIElement), UIElement.PreviewKeyDownEvent, new KeyEventHandler(Grid_PreviewKeyDown));
       base.OnStartup(e);
   }
  
   private void Grid_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
   {
       var uie = e.OriginalSource as UIElement;
  
       if (e.Key == Key.Enter)
       {
           e.Handled = true;
           uie.MoveFocus(
           new TraversalRequest(
           FocusNavigationDirection.Next));
       }
   }
  

• Compile. And done it. Now you can use enter like tab. Note: This work for elements in the grid

Answer 3

I got around woodyiii's issue by adding a FrameworkElement.Tag (whose value is IgnoreEnterKeyTraversal) to certain elements (buttons, comboboxes, or anything I want to ignore the enter key traversal) in my XAML. I then looked for this tag & value in the attached property. Like so:

    if (e.Key == Key.Enter)
    {
        if (ue.Tag != null && ue.Tag.ToString() == "IgnoreEnterKeyTraversal")
        {
            //ignore
        }
        else
        {
            e.Handled = true;
            ue.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }
    }

Answer 4

woodyiii, There is a function in the UIElement called PredictFocus() which by its name know its function, then you can check if that element is enabled or not so as to move the focus to it or not...

Answer 5

Here is Matt Hamilton's code, if anyone is wondering since his site is down apparently:

public class EnterKeyTraversal
{
    public static bool GetIsEnabled(DependencyObject obj)
    {
        return (bool)obj.GetValue(IsEnabledProperty);
    }

    public static void SetIsEnabled(DependencyObject obj, bool value)
    {
        obj.SetValue(IsEnabledProperty, value);
    }

    static void ue_PreviewKeyDown(object sender, System.Windows.Input.KeyEventArgs e)
    {
        var ue = e.OriginalSource as FrameworkElement;

        if (e.Key == Key.Enter)
        {
            e.Handled = true;
            ue.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
        }
    }

    private static void ue_Unloaded(object sender, RoutedEventArgs e)
    {
        var ue = sender as FrameworkElement;
        if (ue == null) return;

        ue.Unloaded -= ue_Unloaded;
        ue.PreviewKeyDown -= ue_PreviewKeyDown;
    }

    public static readonly DependencyProperty IsEnabledProperty =
        DependencyProperty.RegisterAttached("IsEnabled", typeof(bool),

        typeof(EnterKeyTraversal), new UIPropertyMetadata(false, IsEnabledChanged));

    static void IsEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var ue = d as FrameworkElement;
        if (ue == null) return;

        if ((bool)e.NewValue)
        {
            ue.Unloaded += ue_Unloaded;
            ue.PreviewKeyDown += ue_PreviewKeyDown;
        }
        else
        {
            ue.PreviewKeyDown -= ue_PreviewKeyDown;
        }
    }
}