XAML Textbox control KeyDown event is fired twice when Enter key is pressed

Question

Hi,

In my test metro app I have a text box control and have added a handler for the KeyDown event. After a user enters some data into this text box, I am expecting him to press the 'enter' key after which I parse this data. However, I am noticing that only in the case when the 'Enter' key is pressed the KeyDown event is fired twice leading to the handler being invoked twice. When I use any other key, say Windows.System.VirtualKey.Space the event is fired only once as expected.

For example, in XAML I have:

<TextBox x:Name="Test" KeyDown="KeyboardKey_Pressed">

and my CS event handler code looks like this:

private void KeyboardKey_Pressed(object sender, KeyRoutedEventArgs e)
        {
            if (e.Key == Windows.System.VirtualKey.Enter)
            {
                VerifyAnswer(e);               
                return;
            }
            else if ((e.Key == Windows.System.VirtualKey.Delete)
                  || (e.Key == Windows.System.VirtualKey.Back))
            {
                HideVerdict();
            }
        }

 If I put a breakpoint near the VerifyAnswer() statement, it hits twice when the keyboard 'Enter' key is pressed. I am using a physical keyboard attached to my desktop.

Any ideas as to why this event is fired twice? Is there something that I may be missing here?

Build info:

Desktop PC with Windows 8 RP, AMD64, Visual Studio Express 2012 RC

Thanks,
Srini

 

Answer 1

Hi Srini,

Did you try above scenario while debugging in Simulator? I was not able to replicate the issue while debugging using "Local Machine" as target.

-Sagar

Answer 2

Hi Sagar,

Yes I ran this under the VS debugger (local machine) and only when the 'enter' keystroke is pressed the handler is invoked twice. In my above code, I put the breakpoint on VerifyAnswer(e) and it's getting hit twice.

Thanks,
Srini

Answer 3

Hi Srini,

See this previous MSDN thread for the answer to your question:

http://social.msdn.microsoft.com/Forums/en-US/winappswithcsharp/thread/734d6c7a-8da2-48c6-9b3d-fa868b4dfb1d

Thanks,
Andre