Need Help With Certain Keys in Keypress Event

[Klogg]

I don't know how to get the keypress event to determine if certain keys were pressed. I know about the KeyPreview property, and I know how to check if keys like the letter, number, or backspace keys were pressed, but I don't know how to do the delete key, arrow keys, and that kind of stuff. The ones that I need to use right now are the up and down arrow keys.

[Volte]

You need to use the KeyCode event, and use the Keys enumeration to see which key is being pressed. Look at the MSDN.

[Klogg]

I found out in MSDN that the KeyPress event doesn't see keys that don't have an output on the screen, such as the arrow keys, the Delete key, and the function keys. I need to use KeyDown or KeyUp instead for those. However, I found that when I use KeyDown, it only executes the code for the arrow keys if one of the text boxes on my form has the focus. It works fine in the KeyUp event, but then the focus moves if the arrow key is held down long enough, and I don't want it to do that.

[Darc]

I've had some problems with KeyDown and KeyUp before... In some apps they just don't work, and in others they work fine. I haven't pinpointed the problem yet

[Voca]

This is some Code where i want to know if a function key is pressed and then do something.

 

...

if e.KeyData = Keys.Down or e.KeyData = Keys.F8 then

'do something

...

 

This Code can be found within the KeyUp-Event of my Form and is working.

 

Voca

[Voca]

This is some Code where i want to know if a function key is pressed and then do something.

 

...

if e.KeyData = Keys.Down or e.KeyData = Keys.F8 then

'do something

...

 

This Code can be found within the KeyUp-Event of my Form and is working.

 

Voca

 

I forgot, the KeyPreview Property of my form is set to true.

 

Voca

[Klogg]

Actually, that doesn't help me with the problem that I have now. I can't get the arrow keys to work in the KeyDown event when a button has the focus. It only works when a text box has the focus. I am using:

 

If e.KeyCode = Keys.Up

I also tried e.KeyData and e.KeyValue, but they do the same thing. What is the difference between them anyway?

[Klogg]

I found out from another post how to do it.

 

Protected Overrides Function ProcessKeyPreview(ByRef m As System.Windows.Forms.Message) As Boolean
     If m.WParam.ToInt32 = Keys.Up Then
           'whatever the code is
     End If
End Function

[Klogg]

Oops. When I use the code on my last reply, the keys in my KeyPress event don't work for some reason. Well, actually, the fist time it should execute (unless an arrow key has been pressed), it works, but then it doesn't anymore.

[deBUGger]

No, klogg... That happens to work! And thanks to you, now I can move my racket in my pong game! Yeyyyyyyy!!!!!!!!!!!!!!! :)

[sizer]

this is function that returns value ( bool )

 

try with this:

 

Protected Overrides Function ProcessKeyPreview(ByRef m As System.Windows.Forms.Message) As Boolean
     If m.WParam.ToInt32 = Keys.Up Then
           'whatever the code is
     End If
Return True
End Function

[Klogg]

This doesn't seem to make any difference, even if I put Return False.

[CattleRustler]

Protected Overrides Sub OnKeyPress(ByVal e As System.Windows.Forms.KeyPressEventArgs)
           If Asc(e.KeyChar) = CInt(System.Windows.Forms.Keys.Escape) Then
               Me.Close() ' Esc was pressed
           End If

           If Asc(e.KeyChar) = 112 Then 'p was pressed (toggles blnPause value)
               If blnPause = True Then
                   blnPause = False
                   Exit Sub
               Else
                   blnPause = True
               End If
           End If
       End Sub 'OnKeyPress

 

this works for me

[Klogg]

That one works for the Escape key, but not the arrow keys.

[sizer]

try with this

 

Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, ByVal keyData As System.Windows.Forms.Keys) As Boolean

''Implement your code here
'' If keyData = Keys.Escape Then .....

       MessageBox.Show(keyData.ToString)
  

Return True
End Function

Edited November 13, 2003 by sizer

[Klogg]

Getting closer... Now it works, but it blocks keyboard shortcuts to menu items. Also, I can't figure out the Keys.Whatever command for the "(," ")," and "^" keys.

[DiverDan]

The easiest way to use the arrow keys is through the keyup event. This way you can also utilize the keydown and keypress events.

 

An example:

   Private Sub PIValue_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyUp

       If e.KeyCode = Keys.Right Or e.KeyCode = Keys.Up Then
           If tbarPI.value < 50 Then
               tbarPI.value += 1
           End If
       ElseIf e.KeyCode = Keys.Left Or e.KeyCode = Keys.Down Then
           If tbarPI.value >= 1 Then
               tbarPI.value -= 1
           End If
       End If
   End Sub

[Klogg]

I want to use the KeyDown event, but the arrow keys don't work in it unless one of the text boxes has the focus. Maybe I should just just leave this feature out of my program. It's getting to be more trouble than it's worth. Why does something so simple have to be so complicated to do anyway?

[vincentnl]

I too don;t think the correlation between windows controls and catching key_down events has been sufficiently explained.

 

Anybody any information?