Windows窗体删除绘制的椭圆

Question

我在Windows窗体上创建了一些省略号

我希望在鼠标悬停时可选，如果我选择任何椭圆，它将从窗口中删除

下面是在c#中创建椭圆的一些代码

public void DrawCircle_Paint(object sender, PaintEventArgs e)
{
    Pen pen = new Pen(Color.Black, 3); Graphics gr = this.CreateGraphics(); gr.DrawEllipse(pen, 40, 45, 20, 20);
    Pen pen2 = new Pen(Color.Black, 3); Graphics gr1 = this.CreateGraphics(); gr.DrawEllipse(pen2, 30, 25, 38, 20);
    Pen pen3 = new Pen(Color.Black, 3); Graphics gr2 = this.CreateGraphics(); gr.DrawEllipse(pen3, 35, 36, 68, 15);
    Pen pen4 = new Pen(Color.Black, 3); Graphics gr3 = this.CreateGraphics(); gr.DrawEllipse(pen4, 50, 60, 67, 35);
}

Answer 1

你可以使用

this.Invalidate();

这应该能证明他们是清白的。

要么这样，要么

Graphics.Clear();

编辑：

实际上，另一种方法是在鼠标悬停时在内部放置一个布尔值，并使用该布尔值来指示何时绘制椭圆。作为一般说明，您应该将椭圆图形放在onpaint的覆盖中。现在，现在，如果你要使屏幕失效(无论是你自己还是Windows)，你的形状就会消失。在绘画上使用的示例。

bool paint = false;
protected override void OnPaint(object sender, PaintEventArgs e)
{
    if (paint) 
    {
          Pen pen = new Pen(Color.Black, 3); Graphics gr = this.CreateGraphics(); gr.DrawEllipse(pen, 40, 45, 20, 20);
          Pen pen2 = new Pen(Color.Black, 3); Graphics gr1 = this.CreateGraphics(); gr.DrawEllipse(pen2, 30, 25, 38, 20);
          Pen pen3 = new Pen(Color.Black, 3); Graphics gr2 = this.CreateGraphics(); gr.DrawEllipse(pen3, 35, 36, 68, 15);
          Pen pen4 = new Pen(Color.Black, 3); Graphics gr3 = this.CreateGraphics(); gr.DrawEllipse(pen4, 50, 60, 67, 35);
    }
}

我不记得它的具体参数了，但是在你的OnMouseHover (你想关闭省略的地方)

OnMouseHover(){
    ...
    paint = false;
    this.Invalidate(); 
}