C# WinForm 绘制圆角窗体

public void SetWindowRegion()
{
System.Drawing.Drawing2D.GraphicsPath FormPath;
FormPath = new System.Drawing.Drawing2D.GraphicsPath();
Rectangle rect = new Rectangle(0, 22, this.Width, this.Height - 22);//this.Left-10,this.Top-10,this.Width-10,this.Height-10);
    FormPath = GetRoundedRectPath(rect, 30);
this.Region = new Region(FormPath);
}
private GraphicsPath GetRoundedRectPath(Rectangle rect, int radius)
{
int diameter = radius;
Rectangle arcRect = new Rectangle(rect.Location, new Size(diameter, diameter));
GraphicsPath path = new GraphicsPath();
//   左上角
    path.AddArc(arcRect, 180, 90);
//   右上角
    arcRect.X = rect.Right - diameter;
path.AddArc(arcRect, 270, 90);
//   右下角
    arcRect.Y = rect.Bottom - diameter;
path.AddArc(arcRect, 0, 90);
//   左下角
    arcRect.X = rect.Left;
path.AddArc(arcRect, 90, 90);
path.CloseFigure();
return path;
}
protected override void OnResize(System.EventArgs e)
{
this.Region = null;
SetWindowRegion();
}

教你一招:构造圆角窗体 
http://topic.csdn.net/t/20041128/19/3596094.html 

增加命名空间:using System.Drawing.Drawing2D; 
添加方法如下:当然各角的点可根据需要确定.

复制  保存

private void Type(Control sender, int p_1, double p_2)
{
GraphicsPath oPath = new GraphicsPath();
oPath.AddClosedCurve(
new Point[] {
new Point(0, sender.Height / p_1),
new Point(sender.Width / p_1, 0),
new Point(sender.Width - sender.Width / p_1, 0),
new Point(sender.Width, sender.Height / p_1),
new Point(sender.Width, sender.Height - sender.Height / p_1),
new Point(sender.Width - sender.Width / p_1, sender.Height),
new Point(sender.Width / p_1, sender.Height),
new Point(0, sender.Height - sender.Height / p_1) },
(float) p_2);
sender.Region = new Region(oPath);
}

在窗体的paint和resize事件中增加:Type(this,20,0.1); 
参数20和0.1也可以根据自己的需要调整到最佳效