Have c# Windows Control ignore input
I have Windows Application written in c# which displays a form full-screen divided into six equal segments. Each segment has a combination of textbox, listbox, and button controls. I have six wireless keyboards plugged into the machine and each keyboard controls one of the segments.
I have used the Raw Input example proviced on http://www.codeproject.com/KB/system/rawinput.aspx?fid=375378&df=90&mpp=25&noise=3&sort=Position&view=Quick&select=2834754&fr=1#xx0xx to capture keyboard events and forward to the appropriate segment on the screen.
The problem is focus. If one of the controls has focus and a keyboard key is clicked the raw input gets forwarded to the control however the control also gets the input resulting in a duplicate keystroke being processed. To illustrate, if a textbox has the focus and I click the letter A the textbox shows "AA".
I can't seem to figure this out property so I wondered if there is a way I could make this user control simply ignore input it received directly.
Thank you for any help!
I have used the Raw Input example proviced on http://www.codeproject.com/KB/system/rawinput.aspx?fid=375378&df=90&mpp=25&noise=3&sort=Position&view=Quick&select=2834754&fr=1#xx0xx to capture keyboard events and forward to the appropriate segment on the screen.
The problem is focus. If one of the controls has focus and a keyboard key is clicked the raw input gets forwarded to the control however the control also gets the input resulting in a duplicate keystroke being processed. To illustrate, if a textbox has the focus and I click the letter A the textbox shows "AA".
I can't seem to figure this out property so I wondered if there is a way I could make this user control simply ignore input it received directly.
Thank you for any help!
HainKurt
looks like there is a logic problem on your app... what are you doing after getting the key event... maybe you are adding a key and one is added automatically... do you have any code sample, it is very difficult (if not impossible) to suggest something w/o seeing any code...
ASKER
Let's take the listbox as an example. If I get a KeyUp event and the focus is on the listbox I have set my code to do nothing. So I do not process the keystroke. Despite this the keystroke is processed by the control itself and the selected item moves up.
Basically it seems like I can't flag the event as "handled" at the form level so the control gets it anyway! I want my form to handle all keystrokes instead of the controls themselves dealing with them.
Basically it seems like I can't flag the event as "handled" at the form level so the control gets it anyway! I want my form to handle all keystrokes instead of the controls themselves dealing with them.
I suggest you Implement IMessageFilter, which lets you "peek" at ALL messages intended for your entire app BEFORE they get routed to the current form/control. You can suppress messages so they don't get routed at all. It looks like your raw input code will trigger a WM_INPUT message. Try filtering out the "regular" keystrokes by suppressing WM_KEYDOWN, WM_KEYUP, WM_SYSKEYDOWN and WM_SYSKEYUP.
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ASKER
Idle_Mind, I should have mentioned that when I implemented the IMessageFilter my Raw Inputs also ceased so my application was getting no events at all. Thank you for taking the time to write!