When I run this code I get this error.  If I comment out DoubleBuffer, the
program works fine.  Can anyone figure out why it is failing?

Error message:
An unhandled exception of type 'System.ArgumentException' occurred in
system.drawing.dll
Additional information: Invalid parameter used.

Code:  (This code works if you put it into a new application and add a
timer.  Also import System.Drawing.Drawing2D)

Dim RotAng As Decimal = 1.0F
Private Sub Form1_Paint(ByVal sender As Object, ByVal e As
System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint

Dim canvas As Graphics = e.Graphics

Dim paintBrush As New SolidBrush(Color.Black)

Dim pen1 As New Pen(Color.Black)

Dim gpath As New GraphicsPath

Dim XPoints1(3) As PointF

XPoints1(0) = New PointF(6, 6)

XPoints1(1) = New PointF(0, 6)

XPoints1(2) = New PointF(0, 9)

XPoints1(3) = New PointF(6, 9)

Dim myMatrix As New Matrix

Dim myMatrix2 As New Matrix

Dim rotatePoint As New PointF(3.0F, 7.5F)

myMatrix.RotateAt(RotAng, rotatePoint, MatrixOrder.Append)

gpath.AddPolygon(XPoints1)

gpath.Transform(myMatrix)

myMatrix2.Translate(50, 50)

myMatrix2.Scale(4, 4)

gpath.Transform(myMatrix2)

'e.Graphics.FillPath(paintBrush, gpath)

e.Graphics.DrawPath(pen1, gpath)

paintBrush.Dispose()

pen1.Dispose()

canvas.Dispose()

RotAng = RotAng + 3.0F Mod 360.0

End Sub

Private Sub Form1_Resize(ByVal sender As Object, ByVal e As
System.EventArgs) Handles MyBase.Resize

Invalidate()

End Sub

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

Me.Invalidate()

End Sub

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Handles MyBase.Load

Me.SetStyle(ControlStyles.DoubleBuffer, True)

Me.SetStyle(ControlStyles.UserPaint, True)

Me.SetStyle(ControlStyles.AllPaintingInWmPaint, True)

Me.UpdateStyles()

End Sub

This code rotates a simple box drawn with a graphics path and pen.

Thanks!

Chris