当文本框“跳转”到文本框WPF网格时，激发事件KeyDown出现问题

Question

I have a Grid which contains like few TextBoxes below each other :

By pressing Enter I need to jump from txt1 to txt2, from txt2 to txt3 and so on, and I solved it like this:

private void Grid_PreviewKeyDown_1(object sender, KeyEventArgs e)
{
    try
    {
        if (e.Key == Key.Enter)
        {
            UIElement element = e.Source as UIElement;

            element.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
            //e.Handled = true;

        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

And my issue is here, on each of txt boxes by pressing Enter I should calculate something from another txtBoxes, and when I press enter on txt1 it is gonna jump on txt2 and immediatelly call txt2_KeyDown event, which I want to avoid.. I want to call txt2_KeyDown event when I'm 'standing' on txt2 and when I press enter..

ie:

private void txt2_KeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Return)
    {
        try
        {

            CalculateSomethingFromOtherTextBoxes();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }
}

This above is being fired when I am 'standing' on txt1 and when I want to jump to txt2 by pressing Enter, how can I just 'jump' without calling txt2 KeyDown event If I did not press Enter while I am really 'standing' on 'txt2'.

Thanks guys, Cheers

Answer 1

The problem is because of a KeyDown event that you attached to textboxes.

Instead, remove this event and add PreviewKeyDown event.

So, your method signature should be something like this:

private void txt2_PreviewKeyDown(object sender, KeyEventArgs e)
{
   if (e.Key == Key.Return)
        {
            try
            {

               CalculateSomethingFromOtherTextBoxes();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
}

I tested it and it is working as expected.

Answer 2

And my issue is here, on each of txt boxes by pressing Enter I should calculate something from another txtBoxes, and when I press enter on txt1 it is gonna jump on txt2 and immediatelly call txt2_KeyDown event, which I want to avoid.. I want to call txt2_KeyDown event when I'm 'standing' on txt2 and when I press enter..

Then you could handle the LostKeyboardFocus event of "txt2" instead of handling the KeyDown event:

private Key key;
private void Grid_PreviewKeyDown(object sender, KeyEventArgs e)
{
    key = e.Key;
    if (key == Key.Enter)
    {
        UIElement element = e.OriginalSource as UIElement;
        element.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
    }

}

private void txt2_LostKeyboardFocus(object sender, KeyboardFocusChangedEventArgs e)
{
    if (key == Key.Enter)
    {
        CalculateSomethingFromOtherTextBoxes();
    }
}