C# 无边框窗体边框阴影效果的简单实现

通过下面代码在构造函数中调用方法 setshadow();

即可实现无边框窗体的阴影效果了

需要添加命名空间 using system.runtime.interopservices;

private const int cs_dropshadow = 0x20000;
        private const int gcl_style = (-26);       

        [dllimport("user32.dll", charset = charset.auto)]
        public static extern int setclasslong(intptr hwnd, int nindex, int dwnewlong);
        [dllimport("user32.dll", charset = charset.auto)]
        public static extern int getclasslong(intptr hwnd, int nindex);   

        private void setshadow()
        {
            setclasslong(this.handle, gcl_style, getclasslong(this.handle, gcl_style) | cs_dropshadow);
        }