TextBox.OnKeyDown Event

Question

Hi all,

I am currently using .Net Framework 3.5 and designing my application in WPF. I noticed that for a textbox, the OnKeyDown event no longer detects spacebar and backspace keyboard button clicks. I checked back with the .Net Framework 2.0 WinForm textbox OnKeyDown event and it detects that spacebar and backspace keyboard button clicks.

I checked the OnKeyUp event for the WPF and noticed that it does detect the spacebar and backspace keyboard button clicks, but not the OnKeyDown event. Is this a bug?

Thanks!

Best Regards

Answer 1

Hi,

I noticed that the PreviewKeyDown event does detect the spacebar keyboard input but not the KeyDown event for the WPF application. I am currently using it now and it works fine for me but I was just wondering why the KeyDown event does not detect it.

Thanks.

Answer 2

PreviewKeyDown sets the Handled to true (Window converts the spacebar keydown to click event, as far as i know) on the event if it encounters keys such as "space bar".

You can ovveride that by attaching a KeyDown Event Handler in code as shown.

tx.AddHandler(TextBox.KeyDownEvent, new KeyEventHandler(TextBox_KeyDown),true);

The third argument tells that you wish to invoke the event handler even for the handled events. May not be a good idea, but it works in your case. You might want to read more about handledEventsToo.

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