例如马赛克效果中它一直提醒找不到bitmap
            try

{

MyBitmap = (Bitmap)this.pictureBox1.Image.Clone();

int dh = MyBitmap.Height / 20;

int dw = MyBitmap.Width;

Graphics g = this.pictureBox1.CreateGraphics();

g.Clear(Color.Gray);

Point[] MyPoint = new Point[20];

for (int y = 0; y < 20; y++)

{

MyPoint[y].X = 0;

MyPoint[y].Y = y * dh;

}

Bitmap bitmap = new Bitmap(MyBitmap.Width, MyBitmap.Height);

for (int i = 0; i < dh; i++)

{

for (int j = 0; j < 20; j++)

{

for (int k = 0; k < dw; k++)

{

bitmap.SetPixel(MyPoint[j].X + k, MyPoint[j].Y + i, MyBitmap.GetPixel(MyPoint[j].X + k, MyPoint[j].Y + i));

}

}

this.pictureBox1.Refresh();

this.pictureBox1.Image = bitmap;

System.Threading.Thread.Sleep(100);

}

}

catch (Exception ex)

{

MessageBox.Show(ex.Message, "信息提示");

}