Up Down Left and Right arrow keys do not trigger KeyDown event

Question

I am building an application where all the key input must be handled by the windows itself   I set tabstop to false for each control witch could grab the focus except a panel  but I don t know if it has effect    I set KeyPreview to true and I am handling the KeyDown event on this form   My problem is that sometimes the arrow key aren t responsive anymore    The keydown event is not fired when I pressed only an arrow key  The keydown event is fired if I press an arrow key with the control modifier    Have you an idea why my arrow key suddenly stop firing event

User · Answer

I was having the exact same problem  I considered the answer  Snarfblam provided  however  if you read the documentation on MSDN  the ProcessCMDKey method is meant to override key events for menu items in an application   I recently stumbled across this article from microsoft  which looks quite promising  http   msdn microsoft com en-us library system windows forms control previewkeydown aspx  According to microsoft  the best thing to do is set e IsInputKey true  in the PreviewKeyDown event after detecting the arrow keys  Doing so will fire the KeyDown event   This worked quite well for me and was less hack-ish than overriding the ProcessCMDKey

User · Answer

I had a similar issue when calling the WPF window out of WinForms   var wpfwindow   new ScreenBoardWPF IzbiraProjekti        ElementHost EnableModelessKeyboardInterop wpfwindow       wpfwindow Show      However  showing window as a dialog  it worked  var wpfwindow   new ScreenBoardWPF IzbiraProjekti        ElementHost EnableModelessKeyboardInterop wpfwindow       wpfwindow ShowDialog      Hope this helps

User · Answer

protected override bool IsInputKey Keys keyData        if    keyData  amp  Keys Up     Keys Up               keyData  amp  Keys Down     Keys Down               keyData  amp  Keys Left     Keys Left               keyData  amp  Keys Right     Keys Right           return true      else         return base IsInputKey keyData

User · Answer

The best way to do  I think  is to handle it like the MSDN said on http   msdn microsoft com en-us library system windows forms control previewkeydown aspx  But handle it  how you really need it  My way  in the example below  is to catch every KeyDown  -            lt summary gt          onPreviewKeyDown          lt  summary gt           lt param name  e  gt  lt  param gt      protected override void OnPreviewKeyDown PreviewKeyDownEventArgs e                e IsInputKey   true                  lt summary gt          onKeyDown          lt  summary gt           lt param name  e  gt  lt  param gt      protected override void OnKeyDown KeyEventArgs e                Input SetFlag e KeyCode           e Handled   true                  lt summary gt          onKeyUp          lt  summary gt           lt param name  e  gt  lt  param gt      protected override void OnKeyUp KeyEventArgs e                Input RemoveFlag e KeyCode           e Handled   true

User · Answer

Unfortunately  it is quite difficult to accomplish this with the arrow keys  due to restrictions in KeyDown events  However  there are a few ways to get around this    As  Snarfblam stated  you can override the ProcessCmdKey method  which retains the ability to parse arrow key presses  As the accepted answer from this question states  XNA has a built-in method called Keyboard GetState    which allows you to use arrow key inputs  However  WinForms doesn t have this  but it can be done through a P Invoke  or by using a class that helps with it    I recommend trying to use that class  It s quite simple to do so   var left   KeyboardInfo GetKeyState Keys Left   var right   KeyboardInfo GetKeyState Keys Right   var up   KeyboardInfo GetKeyState Keys Up   var down   KeyboardInfo GetKeyState Keys Down    if  left IsPressed      do something         etc      If you use this in combination with the KeyDown event  I think you can reliably accomplish your goal

User · Answer

protected override bool IsInputKey Keys keyData                switch  keyData                        case Keys Right              case Keys Left              case Keys Up              case Keys Down                  return true              case Keys Shift   Keys Right              case Keys Shift   Keys Left              case Keys Shift   Keys Up              case Keys Shift   Keys Down                  return true                    return base IsInputKey keyData             protected override void OnKeyDown KeyEventArgs e                base OnKeyDown e           switch  e KeyCode                        case Keys Left              case Keys Right              case Keys Up              case Keys Down                  if  e Shift                                                       else                                                     break

User · Answer

In order to capture keystrokes in a Forms control  you must derive a new class that is based on the class of the control that you want  and you override the ProcessCmdKey     protected override bool ProcessCmdKey ref Message msg  Keys keyData          handle your keys here     Example    protected override bool ProcessCmdKey ref Message msg  Keys keyData          capture up arrow key     if  keyData    Keys Up                 MessageBox Show  You pressed Up arrow key            return true             return base ProcessCmdKey ref msg  keyData       Full source   Arrow keys in C   Vayne

User · Answer

I m using PreviewKeyDown      private void  calendar PreviewKeyDown object sender  PreviewKeyDownEventArgs e           switch  e KeyCode               case Keys Down              case Keys Right                    action                 break              case Keys Up              case Keys Left                    action                 break

User · Answer

See Rodolfo Neuber s reply for the best answer     My original answer    Derive from a control class and you can override the ProcessCmdKey method  Microsoft chose to omit these keys from KeyDown events because they affect multiple controls and move the focus  but this makes it very difficult to make an app react to these keys in any other way

User · Answer

i had the same problem and was already using the code in the selected answer    this link was the answer for me  maybe for others also   How to disable navigation on WinForm with arrows in C

[c#] Up, Down, Left and Right arrow keys do not trigger KeyDown event

Examples related to c#

Examples related to winforms

Examples related to keydown