C# 开发圆角控件(窗体)的具体实现

最近在做卡片视图的程序，要求将控件做成带有圆角的效果，下面是我在网上查找的资料，经过测试，确定可以实现功能。其中方法三既适应于控件，也适应于窗体。

先上传效果图：

方法一：

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.

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

方法二：

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;

        }

在窗体的resize事件中增加:setwindowregion(); 

方法三：通过window系统api行数，修改控件和窗体为椭圆形状。代码如下所示：

[system.runtime.interopservices.dllimport("gdi32")]
        private static extern intptr beginpath(intptr hdc);
        [system.runtime.interopservices.dllimport("gdi32")]
        private static extern int setbkmode(intptr hdc, int nbkmode);
        const int transparent = 1;
        [system.runtime.interopservices.dllimport("gdi32")]
        private static extern intptr endpath(intptr hdc);
        [system.runtime.interopservices.dllimport("gdi32")]
        private static extern intptr pathtoregion(intptr hdc);
        [system.runtime.interopservices.dllimport("gdi32")]
        private static extern int ellipse(intptr hdc, int x1, int y1, int x2, int y2);
        [system.runtime.interopservices.dllimport("user32")]
        private static extern intptr setwindowrgn(intptr hwnd, intptr hrgn, bool bredraw);
        [system.runtime.interopservices.dllimport("user32")]
        private static extern intptr getdc(intptr hwnd);

protected override void onpaint(painteventargs e)
        {
            base.onpaint(e);

            intptr dc;
            intptr region;

            dc = getdc(this.handle);
            beginpath(dc);
            setbkmode(dc, transparent);
            ellipse(dc, 0, 0, this.width - 3, this.height - 2);
            endpath(dc);
            region = pathtoregion(dc);
            setwindowrgn(this.handle, region, false);
        }