Dim g As Graphics = Me.PictureBox2.CreateGraphics()
g.DrawImage(Me.PictureBox1.Image, New Rectangle(0, 0, 100, 100), New Rectangle(50, 50, 150, 150), GraphicsUnit.Pixel)
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New Rectangle(0, 0, 100, 100)表示PictureBox2中的显示的区域
New Rectangle(50, 50, 150, 150)表示picturebox1中被复制的区域