Graphics Help Please

[SourSW]

I have two forms: MainForm and SubForm

MainForm will create & display the SubForm when a user clicks a button. In SubForm's load event, I draw a bunch of graphics. My problem is that the graphics never show. When I move my graphics code to the MainForm, and have it access SubForm's variables, the graphics appear. InvokeRequired comes back false. I'm stumped why I cannot draw the graphics from SubForm. Anyone have any ideas? Thanx.

[jmcilhinney]

Obviously it's possible, but you must be using incorrect code. Without seeing what code you're using it's not really possible to know what the issue might be.

[SourSW]

Here's the code from SubForm:

Public cG As Graphics
Public draw As New Pen(Color.Black, 3)
Public points As PointF()

Private Sub frmCG_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim index As Integer
ReDim points(5)

Me.cG = Me.pnlcG.CreateGraphics

For index = 0 To 5
points(index).X = (index + 1) << (index + 1)
points(index).Y = 20 * index
Next

Me.cG.DrawLines(Me.draw, Me.points)

End Sub



And Here's MainForm loading subForm:


Private WithEvents frmCG As formCG '//Globally Declared

Me.frmCG = New formCG '//Included in some other func before next one executes

Private Sub clbPopUps_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles clbPopUps.SelectedIndexChanged

If (Me.clbPopUps.GetItemChecked(0)) Then
Me.frmCG.Show()
Else
Me.frmCG.Hide()
EndIf

End Sub

[jhammer]

The form has a Paint event. You are passed a PaintEventArgs which contains a Graphics property.
This event is raised whenever the form needs to repaint itself.

You should use it to handle all GDI graphics.
Pass all the drawing to this event instead of Form_Load. It might solve your problem.

[SourSW]

Thanx, that worked. I replaced my Graphics variable with the one supplied with the PaintEventArgs in my panel Paint event. I guess the graphics code in the form load was executing but because a paint event would be raised afterwards, it just simply overwrote the graphics.