C# 边框阴影窗体效果

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace test
{
public partial class Form3 : Form
{
public Form3()
{
InitializeComponent();
SetClassLong(this.Handle, GCL_STYLE, GetClassLong(this.Handle, GCL_STYLE) | CS_DropSHADOW); //API函数加载，实现窗体边框阴影效果
}

#region 窗体边框阴影效果变量申明

const int CS_DropSHADOW = 0x20000;
const int GCL_STYLE = (-26);
//声明Win32 API
[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);

#endregion

}
}