从面板截图

我试图从一个面板上截图,我在上面画了一些水平线。

我使用了以下代码:

private void linkLabel1_LinkClicked(object sender, LinkLabelLinkClickedEventArgs e)
{
    //hide close button
    pictureBox1.Visible = false;

    //Take screenshoot for the DPanel.
    Bitmap dend = new Bitmap(dPanel.Width, dPanel.Height);
    Graphics G = Graphics.FromImage(dend);
    System.Drawing.Rectangle rectangle = dPanel.RectangleToScreen(dPanel.ClientRectangle);
    G.CopyFromScreen(rectangle.Location, System.Drawing.Point.Empty, dPanel.Size);
    SomeGlobalVariables.Mygraph = dend;

    Reporttoprint r = new Reporttoprint();
    r.Show();
}

单击linkLabel1时发生异常。

似乎当我单击linkLabel1执行代码并从面板中拍摄时,会再次调用dPanel\u Paint action,然后引发异常!

此区域的例外情况:

private void dPanel_Paint(object sender, PaintEventArgs e)
{
    if (k==0)
    {
        //add the "Group" center point to the dictionary.
        ClusterPoint=new Point(((ep1.X+ep2.X)/2),((ep1.Y+ep2.Y)/2));
        //Exception is done here
        clusterpoints.Add(Clusterchar[k], ClusterPoint);
    }
}

任何帮助
提前谢谢。