C# GDI+绘图 为何会有重影

C# GDI+绘图 为什么会有重影？
private void button1_Click(object sender, EventArgs e)
 {
  int height = 400, width = 600;
  Bitmap image = new Bitmap(height, width);
  Graphics g = Graphics.FromImage(image);//创建一个对象
  g.Clear(Color.White);
  Pen mypen = new Pen(new SolidBrush(Color.Blue), 1);
  g.DrawLine(mypen, 100, 80, 100, 340);
  this.panel1.BackgroundImage = image;
}

就是上面这样一段简单的代码，预期是画出一条竖线，可是它却出现了两条，第一次尝试GDI+，求解


[解决办法]
设置panel1的backgroundimagelayout属性，如果是tile,图像会平铺，看上去像两条。
[解决办法]


可以考虑采用“双缓存”技术：

C# code

        private void button1_Click(object sender, EventArgs e)        {            //int height = 400, width = 600;            //Bitmap image = new Bitmap(height, width);            Bitmap image = new Bitmap(DisplayRectangle.Width, DisplayRectangle.Height);            using (Graphics g = Graphics.FromImage(image))            {                g.Clear(Color.White);                Pen mypen = new Pen(new SolidBrush(Color.Blue), 1);                g.DrawLine(mypen, 100, 80, 100, 340);            }            this.panel1.BackgroundImage = image;        }