尝试将绘图逻辑移至

Try moving the drawing logic to the Paint evet.

让我们假设您正在一个名为pnl的面板上绘画.请尝试以下操作:

Let's assume you are drawing on a panel called pnl. Try the following:

在构造函数上注册到绘画绘画专家:

On your constructor register to the paint evet:

 this.pnl.Paint += pnl_Paint;

在单击时，设置一个标志以指示矩形需要绘画:

Upon a click, set a flag to indicate that painting is required for the rectangle:

bool _paintRect;

private void button1_Click(object sender, EventArgs e)
{
    this._paintRect = true;
    Invalidate();        
    Refresh();
}

在paint事件处理程序中，进行实际的绘制:

In the paint event handler, do the actual paint:

private void pnl_Paint(object sender, PaintEventArgs e)
{
   //take screenshot of transparent form area
    Bitmap CapturedScreen = ScreenShot.Create((this.Left + 8), (this.Top + 30), 780, 415);
    ImageData refpic = new ImageData("pallo.bmp");
    ImageData source = new ImageData(CapturedScreen);

    Graphics graphics = e.Graphics;

    Pen p = new Pen(Color.Black, 1);
    graphics.DrawRectangle(p, Template.Image(source, refpic, 100));
}