Question

c# winform 画图形

比如picturebox上面已经有了一张图片，我想做个按钮，点击它，就会出现一个方框，来标注这个图片上的某些区域，怎么做，求代码

Answer 1

private void button1_Click(object sender, EventArgs e)
{

System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(pictureBox1.Image);
g.DrawRectangle(Pens.Red, 5, 5, 55, 55);
pictureBox1.Refresh();
}