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how to trigger function by keypressed

kengkit
kengkit asked
on
Medium Priority
233 Views
Last Modified: 2010-04-23
I gonna pop up the message box everytime i pressed "F12" in my keyboard. ( or i pressed Ctrl + Y")

Private Function testing ()
    Msgbox ("Hello")
End Function

How to do it?
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Mike TomlinsonHigh School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009

Commented:
Do you want this only when YOUR app is in focus?  Or when ANY app is in focus?

Author

Commented:
in fact.. i juz wants tis when my app is in focus

but it's good if u can tell me both.
Top Expert 2006

Commented:
I'm not sure how to do it if your app doesn't have focus (I haven't brushed up on my keyboard hooking), but here's how you can do it if your app has focus:

    Private Function testing()
        Msgbox("Hello")
    End Function

    Protected Overrides Function ProcessCmdKey(ByRef msg As System.Windows.Forms.Message, ByVal keyData As System.Windows.Forms.Keys) As Boolean
        If keyData = Keys.Control + Keys.Y Or keyData = Keys.F12 Then
            testing()
            Return True
        End If
    End Function

Commented:
'U Can use the IMessageFilter Interface for it
' Creates a message filter.
Public Class TestMessageFilter
   Implements IMessageFilter

   Public Function PreFilterMessage(ByRef m As System.Windows.Forms.Message) _
   As Boolean Implements IMessageFilter.PreFilterMessage
      ' Blocks all the messages relating to the left mouse button.
      If ((m.Msg >= 513) And (m.Msg <= 515)) Then
         Console.WriteLine("Processing the messages : " & m.Msg)
         Return True
      End If
      Return False
   End Function
End Class

Try It
High School Computer Science, Computer Applications, Digital Design, and Mathematics Teacher
CERTIFIED EXPERT
Top Expert 2009
Commented:
Here is an example of the hook approach that allows you trap keypresses while your app is not in focus:
http://www.experts-exchange.com/Programming/Programming_Languages/Dot_Net/VB_DOT_NET/Q_21584180.html

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