CODEWITHSUNDEEP
wpfcomboboxrouted-events
xr280xr
xr280xr

Reputation: 13302

ComboBox PreviewKeyDown doesn't fire for Return key

I'm want to conditionally prevent the Enter/Return key from selecting the highlighted item in a ComboBox drop down. So I wired up an event handler to the ComboBox.PreviewKeyDown so that I could set the Handled property, but the event handler is never entered. When I use Snoop to watch the events, the PreviewKeyDown event is fired for other keys but it never fires when I press the return key; not even at the Window level. Why isn't the event firing?

EDIT: The ComboBox needs to be editable (IsEditable=true). Then open the drop down list. Begin typing in an item in your list and it should select it for you. Press the return key.

Upvotes: 3

Views: 2569

Answers (2)

CaesarMyMate
CaesarMyMate

Reputation: 118

That's because WPF internally handles the event when the drop-down is open and enter key is pressed. That's the default WPF behavior.

To solve, extend the ComboBox and override the OnPreviewKeyDown method.

public class MyComboBox : ComboBox
{
    protected override void OnPreviewKeyDown(KeyEventArgs e)
    {
        bool isDropDownOpen = IsDropDownOpen;

        base.OnPreviewKeyDown(e);

        if (isDropDownOpen)
        {
            e.Handled = false;
        }
    }
}

Upvotes: 1

Jayson Ragasa
Jayson Ragasa

Reputation: 1029

Try this

// prevent selecting an item when a comboboxitem is highlighted
protected override void OnPreviewKeyDown(KeyEventArgs e)
{
    if (e.Key == System.Windows.Input.Key.Enter || e.Key == System.Windows.Input.Key.Return)
    {
        e.Handled = true;
    }
    else
    {
        //if (base.IsDropDownOpen == false)
        //{
        //  base.IsDropDownOpen = true;
        //}
    }

    //base.OnPreviewKeyDown(e);
}

Upvotes: 0

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