C# 制作透明窗体

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;
using ControlExs;

namespace TransForm
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();

//// 定义在窗体上，光标显示为手形
this.Cursor = System.Windows.Forms.Cursors.Hand;
//// 定义窗体的标题名称
this.Text = "透明的WinForm窗体！";
//// 定义窗体的开始显示位置是屏幕的中间
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
//// 窗体的边界是Fixed3D类型
//this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
////以桌面的前景色作为窗体的前景色
this.ForeColor = System.Drawing.SystemColors.Desktop;
//// 定义字体类型，大小
this.Font = new System.Drawing.Font("宋体", 9);
//// 定义背景色为蓝色
this.BackColor = System.Drawing.Color.White;
// 设置窗体的大小
//this.ClientSize = new System.Drawing.Size(440, 170);
// Opacity属性设立窗体的透明程度，只对于视窗2000有效
this.Opacity = 0.60;
}

private void Form1_Load(object sender, EventArgs e)
{
this.SetWindowTransparent(100);
}

private void SetWindowTransparent(byte bAlpha)
{
try
{
WinAPI.SetWindowLong(this.Handle, (int)WinAPI.WindowStyle.GWL_EXSTYLE, WinAPI.GetWindowLong(this.Handle, (int)WinAPI.WindowStyle.GWL_EXSTYLE) | (uint)WinAPI.ExWindowStyle.WS_EX_LAYERED);
WinAPI.SetLayeredWindowAttributes(this.Handle, 0, bAlpha, WinAPI.LWA_COLORKEY | WinAPI.LWA_ALPHA);
}
catch
{

}
}

protected override CreateParams CreateParams
{
get
{
CreateParams cp = base.CreateParams;
cp.Parent = WinAPI.GetDesktopWindow();
cp.ExStyle = 0x00000080 | 0x00000008;  //WS_EX_TOOLWINDOW | WS_EX_TOPMOST
return cp;
}
}
}
}

public class WinAPI
{
[DllImport("user32.dll")]
public extern static IntPtr GetDesktopWindow();

[DllImport("user32.dll")]
public extern static bool SetLayeredWindowAttributes(IntPtr hwnd, uint crKey, byte bAlpha, uint dwFlags);

public static uint LWA_COLORKEY = 0x00000001;
public static uint LWA_ALPHA = 0x00000002;

[DllImport("user32.dll")]
public extern static uint SetWindowLong(IntPtr hwnd, int nIndex, uint dwNewLong);

[DllImport("user32.dll")]
public extern static uint GetWindowLong(IntPtr hwnd, int nIndex);

public enum WindowStyle : int { GWL_EXSTYLE = -20 }
public enum ExWindowStyle : uint { WS_EX_LAYERED = 0x00080000 }
}