C# 实现鼠标穿透

#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

private const uint WS_EX_LAYERED = 0x80000;
private const int WS_EX_TRANSPARENT = 0x20;
private const int GWL_EXSTYLE = (-20);

GetWindowLong(this.Handle, GWL_EXSTYLE);
SetWindowLong(this.Handle, GWL_EXSTYLE, WS_EX_TRANSPARENT | WS_EX_LAYERED);