C#窗体全屏功能

全屏窗体代码
   public partial class FrmFullScreen : Form
     {
         Boolean m_IsFullScreen = false;//标记是否全屏
         Rectangle rectOld = Rectangle.Empty;
         public FrmFullScreen()
         {
             InitializeComponent();
         }
         /// <summary>
         /// 全屏按钮的Click事件
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btnFullScreen_Click(object sender, EventArgs e)
         {
             m_IsFullScreen = !m_IsFullScreen;//点一次全屏，再点还原。  
     
             SetFormFullScreen(m_IsFullScreen);
 
             this.SuspendLayout();
             if (m_IsFullScreen)//全屏 
             {
                 this.WindowState = FormWindowState.Maximized; 
                 this.FormBorderStyle = FormBorderStyle.None;
             }
             else//还原 TODO:还原后的窗体应该与全屏前的大小一致
             {
                 this.WindowState = FormWindowState.Normal;
                 this.FormBorderStyle = FormBorderStyle.Sizable;
             }
             this.ResumeLayout(false);
         }
         /// <summary>
         /// 全屏的快捷功能，F11相当于单机按钮；Esc健，如果全屏则退出全屏
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void btnFullScreen_KeyDown(object sender, KeyEventArgs e)
         {
             if (e.KeyCode == Keys.F11)
             {
                 btnFullScreen.PerformClick();
                 e.Handled = true;
             }
             else if (e.KeyCode == Keys.Escape)//esc键盘退出全屏
             {
                 if (m_IsFullScreen)
                 {
                     e.Handled = true;
                     SetFormFullScreen(false);
                     this.WindowState = FormWindowState.Normal;//还原  
                     this.FormBorderStyle = FormBorderStyle.Sizable;
                 }
             }
         }
         /// <summary>  
         /// 设置全屏或这取消全屏  
         /// </summary>  
         /// <param name="fullscreen">true:全屏 false:恢复</param>  
         /// <param name="rectOld">设置的时候，此参数返回原始尺寸，恢复时用此参数设置恢复</param>  
         /// <returns>设置结果</returns>  
         public Boolean SetFormFullScreen(Boolean fullscreen)//, ref Rectangle rectOld
         {
             Rectangle rectOld=Rectangle.Empty;
             Int32 hwnd = 0;
             hwnd = FindWindow("Shell_TrayWnd", null);//获取任务栏的句柄
 
             if (hwnd == 0) return false;
 
             if (fullscreen)//全屏
             {
                 ShowWindow(hwnd, SW_HIDE);//隐藏任务栏
 
                 SystemParametersInfo(SPI_GETWORKAREA, 0, ref rectOld, SPIF_UPDATEINIFILE);//get  屏幕范围
                 Rectangle rectFull = Screen.PrimaryScreen.Bounds;//全屏范围
                 SystemParametersInfo(SPI_SETWORKAREA, 0, ref rectFull, SPIF_UPDATEINIFILE);//窗体全屏幕显示
             }
             else//还原 
             {
                 ShowWindow(hwnd, SW_SHOW);//显示任务栏
 
                 SystemParametersInfo(SPI_SETWORKAREA, 0, ref rectOld, SPIF_UPDATEINIFILE);//窗体还原
             }
             return true;
         }
 
         #region user32.dll
 
         [DllImport("user32.dll", EntryPoint = "ShowWindow")]
         public static extern Int32 ShowWindow(Int32 hwnd, Int32 nCmdShow);
         public const Int32 SW_SHOW = 5; public const Int32 SW_HIDE = 0;
 
         [DllImport("user32.dll", EntryPoint = "SystemParametersInfo")]
         private static extern Int32 SystemParametersInfo(Int32 uAction, Int32 uParam, ref Rectangle lpvParam, Int32 fuWinIni);
         public const Int32 SPIF_UPDATEINIFILE = 0x1;
         public const Int32 SPI_SETWORKAREA = 47;
         public const Int32 SPI_GETWORKAREA = 48;
 
         [DllImport("user32.dll", EntryPoint = "FindWindow")]
         private static extern Int32 FindWindow(string lpClassName, string lpWindowName);
 
         #endregion
     }