C# WInForm 无框窗体移动

调用API
   

using  System.Runtime.InteropServices;

    [DllImport( " user32.dll " )]
      public   static   extern   bool  ReleaseCapture();
    [DllImport( " user32.dll " )]
     public   static   extern   bool  SendMessage(IntPtr hwnd,  int  wMsg,  int  wParam,  int  lParam);
    public   const   int  WM_SYSCOMMAND  =   0x0112 ;
    public   const   int  SC_MOVE  =   0xF010 ;
     public   const   int  HTCAPTION  =   0x0002 ; 

// 在空间的_MouseDown中加入如下代码:


     private   void  Form1_MouseDown( object  sender, System.Windows.Forms.MouseEventArgs e)
   {
    ReleaseCapture();
    SendMessage( this .Handle, WM_SYSCOMMAND, SC_MOVE  +  HTCAPTION,  0 );
   }