移除或删除在PictureBox上绘制的矩形

pictureBox1.Image = null;

Graphics g = pictureBox1.CreateGraphics();
g.Clear(pictureBox1.BackColor);
g.Dispose();

// 存储原始图像
Image originalImage = pictureBox1.Image.Clone() as Image;

// ... 在这里绘制矩形 ...

// 移除矩形时重绘
Graphics g = pictureBox1.CreateGraphics();
g.DrawImage(originalImage, 0, 0);
g.Dispose();

bool drawRectangle = true;

private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
    // ... 其他绘制逻辑 ...

    if (drawRectangle)
    {
        // 绘制矩形的代码
        e.Graphics.DrawRectangle(Pens.Black, new Rectangle(10, 10, 100, 50));
    }
}

// 当你想移除矩形时
drawRectangle = false;
pictureBox1.Invalidate(); // 强制重绘

pictureBox1.DoubleBuffered = true;

using (Graphics g = pictureBox1.CreateGraphics())
{
    // 绘制逻辑
}
// Graphics对象在这里自动释放