c# WinForm 边框阴影窗体

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 testWinForm

{

    public partial class Form2 : Form

    {

        public Form2()

        {

            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 = (-);

        //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

        private void Form2_Load(object sender, EventArgs e)

        {

        }

    }

} 效果：