const int CS_DROPSHADOW = 0x20000;
constint GCL_STYLE = (-26);
//声明Win32 API
[DllImport("user32.dll", CharSet = CharSet.Auto)]
publicstatic extern int SetClassLong(IntPtrhwnd, int nIndex, intdwNewLong);
[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern int GetClassLong(IntPtrhwnd, int nIndex);
//调用
SetClassLong(this.Handle, GCL_STYLE, GetClassLong(this.Handle, GCL_STYLE) | CS_DROPSHADOW);
相关页面:http://hi.baidu.com/xiangboren/blog/item/5eafe2240a5aa4308644f96e.html