实现鼠标穿透窗体

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 MouseThroughForm
{
public partial class Frm_Main : Form
{
public Frm_Main()
{
InitializeComponent();
}

private const uint WS_EX_LAYERED = 0x80000;
private const int WS_EX_TRANSPARENT = 0x20;
private const int GWL_EXSTYLE = (-20);
private string Var_genre = "";//记录当前操作的类型

#region 在窗口结构中为指定的窗口设置信息
/// <summary>
/// 在窗口结构中为指定的窗口设置信息
/// </summary>
/// <param name="hwnd">欲为其取得信息的窗口的句柄</param>
/// <param name="nIndex">欲取回的信息</param>
/// <param name="dwNewLong">由nIndex指定的窗口信息的新值</param>
/// <returns></returns>
[DllImport("user32", EntryPoint = "SetWindowLong")]
private static extern uint SetWindowLong(IntPtr hwnd, int nIndex, uint dwNewLong);
#endregion

#region 从指定窗口的结构中取得信息
/// <summary>
/// 从指定窗口的结构中取得信息
/// </summary>
/// <param name="hwnd">欲为其获取信息的窗口的句柄</param>
/// <param name="nIndex">欲取回的信息</param>
/// <returns></returns>
[DllImport("user32", EntryPoint = "GetWindowLong")]
private static extern uint GetWindowLong(IntPtr hwnd, int nIndex);
#endregion

#region 使窗口有鼠标穿透功能
/// <summary>
/// 使窗口有鼠标穿透功能
/// </summary>
private void CanPenetrate()
{
uint intExTemp = GetWindowLong(this.Handle, GWL_EXSTYLE);
uint oldGWLEx = SetWindowLong(this.Handle, GWL_EXSTYLE, WS_EX_TRANSPARENT | WS_EX_LAYERED);
}
#endregion

private void Frm_Main_Load(object sender, EventArgs e)
{
this.ShowInTaskbar = false;//窗体不出现在Windows任务栏中
CanPenetrate();
this.TopMost = true;//使窗体始终在其它窗体之上
}

#region 设置颜色和透明度的状态
/// <summary>
/// 设置颜色和透明度的状态
/// </summary>
private void SetEstate(Form Frm, object sender)
{
Var_genre = ((ToolStripMenuItem)sender).Name;
string Tem_Str = Var_genre;
if (Var_genre.IndexOf('_') >= 0)
{
Var_genre = Tem_Str.Substring(0, Tem_Str.IndexOf('_'));
}

switch (Var_genre)
{
case "ToolColor":
{
Color Tem_Color=Color.Gainsboro;
switch (Convert.ToInt32(((ToolStripMenuItem)sender).Tag.ToString()))
{
case 1: Tem_Color = Color.Gainsboro; break;
case 2: Tem_Color = Color.DarkOrchid; break;
case 3: Tem_Color = Color.RoyalBlue; break;
case 4: Tem_Color = Color.Gold; break;
case 5: Tem_Color = Color.LightGreen; break;
}
Frm.BackColor = Tem_Color;
break;
}
case "ToolClarity":
{
double Tem_Double = 0.0;
switch (Convert.ToInt32(((ToolStripMenuItem)sender).Tag.ToString()))
{
case 1: Tem_Double = 0.1; break;
case 2: Tem_Double = 0.2; break;
case 3: Tem_Double = 0.3; break;
case 4: Tem_Double = 0.4; break;
case 5: Tem_Double = 0.5; break;
case 6: Tem_Double = 0.6; break;
case 7: Tem_Double = 0.7; break;
case 8: Tem_Double = 0.8; break;
case 9: Tem_Double = 0.9; break;

}
Frm.Opacity = Tem_Double;
break;
}
case "ToolAcquiescence":
{
Frm.BackColor = Color.Gainsboro;
Frm.Opacity = 0.6;
break;
}
case "ToolClose":
{
Close();
break;
}

}
}
#endregion

private void ToolColor_Glass_Click(object sender, EventArgs e)
{
SetEstate(this, sender);
}
}
}