VB2005 maintain focus on hidden app

[jontcaz]

Good Day,
I have an application that will send text out of a serial port if i hold down the "1" key for 2 seconds. I am currently just turning a chime on and off but want to expand this to the ability to turn my amplifier on/off etc. I want this to be running in the background but to respond at any time by just hitting a certain key. The program works great one time when i execute, but goes into hide and i never see it again. Any suggestions are appreciated.

Public Class frmKeyCatcher
Dim WithEvents serialPort As New IO.Ports.SerialPort

Private Sub DataReceived( _
ByVal sender As Object, _
ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) _
Handles serialPort.DataReceived

txtDataReceived.Invoke(New myDelegate(AddressOf updateTextBox), _
New Object() {})
End Sub

Public Delegate Sub myDelegate()
Public Sub updateTextBox()
With txtDataReceived
.SelectionColor = Color.Red
.AppendText(serialPort.ReadExisting)
.ScrollToCaret()
End With
End Sub

Private Sub frmKeyCatcher_FormClosing(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles Me.FormClosing
serialPort.Close()
End Sub


Private Sub frmKeyCatcher_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyDown
If e.KeyCode = 49 Then
Timer1.Start()

End If
End Sub

Private Sub frmKeyCatcher_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles Me.KeyUp
If e.KeyCode = 49 Then
Timer1.Stop()
End If
End Sub

Private Sub Timer1_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Me.Show()
Me.BackColor = Color.LightGray
If serialPort.IsOpen Then
serialPort.Close()
End If
Try
With serialPort
.PortName = "COM3"
.BaudRate = 96000
.Parity = IO.Ports.Parity.None
.DataBits = 8
.StopBits = IO.Ports.StopBits.One

End With

serialPort.Open()
Timer4.Start()
Catch ex As Exception
MsgBox(ex.ToString)
End Try

End Sub

Private Sub Timer2_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer2.Tick
Me.Hide()
Timer2.Stop()
End Sub

Private Sub Timer4_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles Timer4.Tick
Try
serialPort.Write("C")
With txtDataReceived
.SelectionColor = Color.Black
.AppendText("C" & vbCrLf)
.ScrollToCaret()

End With
Me.BackColor = Color.white
Catch ex As Exception

End Try
Timer4.Stop()
Timer2.Start()
End Sub


End Class

[Robbie]

... I want this to be running in the background but to respond at any time by just hitting a certain key. ...

Hi. The code which you posted does not look like VB6 code...

I have a 'Declare Function' which you can use in VB6. I don't know if you can use it in .NET though, because I'm not really advanced with it.

Private Declare Function GetAsyncKeyState Lib "user32" (ByVal vKey As Long) As Integer

You use it by giving it a keycode to check for. It seems to check the keyboard directly, rather than the program having to have focus for it to work. If it gives back -32767, then the key is pressed, otherwise it's not.

So it would be easier to set up a constant of that, e.g.

Const KeyPressed As Integer = -32767

Then check the function against that constant, e.g. to check if the Space key is being pressed:

if GetAsyncKeyState(vbKeySpace) = KeyPressed then
'The key is down
else
'It's not being pressed down
end if

As I said, that's VB6 code, but I hope you can apply it to what you need it for. And I haven't tested, but there is equivalent code in another programming language I'm familiar with, to check the keyboard directly (and I assume this is what this function does), and it works without the program having to have focus.

EDIT: So you'd need to check regularly with a timer or while-doevents-wend loop or such, whether or not the key is currently down.

[jontcaz]

[quote=Robbie]Hi. The code which you posted does not look like VB6 code...

Hey Robbie, thanks for the reply, i guess i should have posted this in .net forum eh? I will try your ideas in 6 to see if that works.