Question

winform在picturebox中画图，最小化或者刷新后消失的问题

画图的代码如下：

private Point p1, p2;//定义两个点（启点，终点）
private static bool drawing=false;//设置一个启动标志
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{ p1 = new Point(e.X, e.Y);
p2 = new Point(e.X, e.Y);
drawing = true; }

private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
drawing = false;
}
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{Graphics g = pictureBox1.CreateGraphics();
if(e.Button ==MouseButtons.Left)
{
if (drawing)
{
//drawing = true;
Point currentPoint = new Point(e.X, e.Y);
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//消除锯齿
g.DrawLine(new Pen(Color.Blue, 2), p2,currentPoint);

p2.X = currentPoint.X;
p2.Y = currentPoint.Y;
} } }
或者不用此代码也行，我的目的就是可以在我picturebox显示的图片上可以自由写画

Answer 1

你这样画的话肯定会消失的啊，把你的代码放到on paint事件里面去

追问

我也百度到要这个onpaint， 但是不会。。可不可以给我说下。。谢谢了，这个问题真的很困扰我