DoEvents not working

[JoshK]

ok I have a time that ticks every 10ms to update one lable with the current mouse position, and also set a panel to the color unser the mouse

 

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

Dim point As Point

point.X = Windows.Forms.Cursor.Position.X

point.Y = Windows.Forms.Cursor.Position.Y

lblMouse.Text = point.X & "," & point.Y

Dim color As Color

color = GetPixelColor(point.X, point.Y)

lblColor.Text = ColorTranslator.ToWin32(Drawing.Color.FromArgb(color.A, color.R, color.G, color.B)).ToString

pnlColor.BackColor = color

System.Windows.Forms.Application.DoEvents()

 

End Sub

 

while thats happening I want to be able to save the current mouse position and the color to a listbox when the user hits the 'w' key

 

Private Sub Form1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles Me.KeyPress

If e.Equals(Keys.W) Then lstCommands.Items.Add(lblmouse.tostring & " :: " & lblcolor.tostring)

End Sub

 

As you can see I put DoEvents() but when I hit the w key nothing happens, I also tried removing the IF in form1_keypress and the keypress just doesnt activate.

 

 

Please help

[snarfblam]

By default the KeyPress event only fires for the control that has focus, which will never be the form if the form has child controls.

 

You should set the form's KeyPreview property to True. This causes the form to intercept all keyboard input and process it before it is sent to child controls, which should be all you need to do to make your program work.

[JoshK]

Great thanks, I'll give it a try. Then, for future reference, what if I have a textbox for some kind of information, what if the user hit one of the keys that I have in KeyPress event. Is there a way to turn KeyPreview on and off in code?

[snarfblam]

One possiblility would be to examine the ActiveControl property and act based on that...

Private Sub Form1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
   If ActiveControl Is TextBox1 Then
       'You probably want to do nothing here
   Else
       If e.KeyCode = Keys.W Then
           'Do things here
       End If
   End If
End Sub

You could also set the KeyPreview property when a TextBox gets or loses focus...

Private Sub TextBox1_Enter(ByVal sender As System.Object, ByVal e As em.EventArgs) Handles TextBox1.Enter
   KeyPreview = False
End Sub

Private Sub TextBox1_Leave(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.Leave
   KeyPreview = True
End Sub

[Cags]

Just so nobody gets confused its not strictly neccessary to alter behaviour for a textbox unless you don't want the form to perform the action when it is focused. Text typed will still appear in the textbox it was just also call the forms keypress. As such if the forms key press only handles shortcut keys and such, you will not need to code special cases for your textboxes. Edited May 2, 2006 by Cags