Option Strict On
Public Class Form1
Inherits System.Windows.Forms.Form
Bitmap holds picture of the Form
Private b1 As Bitmap
Graphics object (buffer)
Private g1 As Graphics
Private Sub Form1_Activated(ByVal sender As Object, _
ByVal e As System.EventArgs) Handles MyBase.Activated
Static done As Boolean = False
If Not done Then
Text = "AutoRedraw Test"
BackColor = System.Drawing.Color.White
Create the initial bitmap from Form
b1 = New Bitmap(Me.Size.Width, _
Me.Size.Height, Me.CreateGraphics())
Create the Graphics Object buffer
which ties the bitmap to it so that
when you draw something on the object
the bitmap is updated
g1 = Graphics.FromImage(b1)
Print something
FormPrint(".NET Printing", 10, 10)
Prevent reentry to initialization
done = True
End If
End Sub
Print something else
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click
FormPrint("2nd Printing", 100, 100)
End Sub
Private Sub FormPrint(ByVal t$, ByVal x1%, ByVal y1%)
Printing to the graphics buffer (not form)
updates the associated bitmap b1
g1.DrawString(t, New Font("Verdana", 12), _
Brushes.Black, x1, y1)
Copy the bitmap to the form
Me.CreateGraphics.DrawImage(b1, 0, 0)
End Sub
Private Sub Form1_Paint( _
ByVal sender As Object, _
ByVal e As System.Windows.Forms.PaintEventArgs) _
Handles MyBase.Paint
Copy the bitmap to the form
e.Graphics.DrawImage(b1, 0, 0)
End Sub
End Class