WPF, How to detect Spacebar press in RichTextBox

Question

In WPF, I have a RichTextBox with a flow document inside. I need to know when the user presses a spacebar. The code below works and shows a messagebox each time a key is pressed but not for spacebar. If you press F e.g. a messagebox with F is displayed but when space is pressed the caret just moves to the next position.

private void RichTextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
            {
                MessageBox.Show(e.Text);
            }

What am I missing here? Thanks for your time :)

score 2 · Accepted Answer · edited May 23 '17 at 10:25

You can detect the space character by handling the PreviewKeyDown or PreviewKeyUp events like this:

private void PreviewKeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Space) 
    {
        // The user pressed the space bar
    }
}

As to why the PreviewTextInput event ignores the space character, you can find some interesting information in the Why does PreviewTextInput not handle spaces? post and the links found there.

WPF, How to detect Spacebar press in RichTextBox

1 Answers1