C # camera screenshot

Using  System;  Using  System. runtime. interopservices;  Using  System. drawing;  Using  System. Drawing. imaging;  Namespace  Video {  ///   <Summary>  ///  A class for controlling cameras  ///   </Summary> Public   Class  Videowork {  Private   Const   Int Wm_user = Zero X 400  ;  Private   Const   Int Ws_child = Zero X 40000000  ;  Private   Const   Int Ws_visible =Zero X 10000000  ;  Private   Const   Int Wm_cap_start = Wm_user;  Private   Const   Int Wm_cap_stop = wm_cap_start + 68  ;  Private   Const   Int Wm_cap_driver_connect = wm_cap_start + 10 ;  Private   Const   Int Wm_cap_driver_disconnect = wm_cap_start + 11  ;  Private   Const   Int Wm_cap_savedib = wm_cap_start + 25  ;  Private   Const   Int Wm_cap_grab_frame = wm_cap_start + 60 ;  Private   Const   Int Wm_cap_sequence = wm_cap_start + 62  ;  Private   Const   Int Wm_cap_file_set_capture_filea = wm_cap_start + 20  ;  Private   Const   Int Wm_cap_sequence_nofile = wm_cap_start + 63 ;  Private   Const   Int Wm_cap_set_overlay = wm_cap_start + 51  ;  Private   Const   Int Wm_cap_set_preview = wm_cap_start + 50  ;  Private   Const   Int Wm_cap_set_callback_videostream = wm_cap_start + 6 ;  Private   Const   Int Wm_cap_set_callback_error = wm_cap_start + 2  ;  Private   Const   Int Wm_cap_set_callback_statusa = wm_cap_start + 3  ;  Private   Const   Int Wm_cap_set_callback_frame = wm_cap_start + 5 ;  Private   Const   Int Wm_cap_set_scale = wm_cap_start + 53  ;  Private   Const   Int Wm_cap_set_previewrate = wm_cap_start + 52  ;  Private  Intptr hwndc;  Private   Bool Bworkstart =False  ;  Private  Intptr mcontrolptr;  Private   Int  Mwidth;  Private   Int  Mheight;  Private   Int  Mleft;  Private   Int  MTop;  ///  <Summary>  ///  Initialize the display image  ///   </Summary>  ///   <Param name = "handle">  Control handle  </Param>  ///   <Param name = "Left">  Left margin of start display  </Param>  ///   <Param name = "TOP">  Top margin of start display </Param>  ///   <Param name = "width">  Width to be displayed  </Param>  ///   <Param name = "height">  Length to be displayed  </Param>  Public Videowork (intptr handle, Int Left, Int Top, Int Width, Int Height) {mcontrolptr = Handle; mwidth = Width; mheight = Height; mleft = Left; MTop = Top;} [dllimport (  "  Avicap32.dll  "  )]  Private   Static   Extern Intptr capcreatecapturew.wa ( Byte [] Lpszwindowname, Int Dwstyle, Int X, Int Y, Int Nwidth, Int Nheight, intptr hwndparent, Int  NID); [dllimport (  "  Avicap32.dll  "  )]  Private   Static   Extern  Int Capgetvideoformat (intptr hwnd, intptr psvideoformat, Int  Wsize); [dllimport (  "  User32.dll  "  )]  Private   Static   Extern   Bool Sendmessage (intptr hwnd, Int Wmsg, Int Wparam, Long Lparam );  ///   <Summary>  ///  Start displaying images  ///   </Summary>  Public   Void  Start (){  If  (Bworkstart)  Return  ; Bworkstart = True  ; Byte [] Lpszname = New   Byte [ 100  ]; Hwndc = Capcreatecapturew.wa (lpszname, ws_child | ws_visible, mleft, MTop, mwidth, mheight, mcontrolptr, 0  );  If (Hwndc. toint32 ()! = 0  ) {Sendmessage (hwndc, wm_cap_set_callback_videostream,  0 , 0  ); Sendmessage (hwndc, wm_cap_set_callback_error, 0 , 0  ); Sendmessage (hwndc, wm_cap_set_callback_statusa,  0 , 0  ); Sendmessage (hwndc, wm_cap_driver_connect,  0 , 0  ); Sendmessage (hwndc, wm_cap_set_scale,  1 , 0  ); Sendmessage (hwndc, wm_cap_set_previewrate,  66 , 0 ); Sendmessage (hwndc, wm_cap_set_overlay,  1 , 0  ); Sendmessage (hwndc, wm_cap_set_preview,  1 , 0  );  //  Global. log. Write ("sendmessage ");  }  Return  ;}  ///   <Summary>  /// Stop display  ///   </Summary>  Public   Void  Stop () {sendmessage (hwndc, wm_cap_driver_disconnect,  0 , 0  ); Bworkstart = False  ;}  ///   <Summary>  ///  Capture images  ///  </Summary>  ///   <Param name = "path">  Path of the BMP file to be saved  </Param>  Public   Void Grabimage ( String  Path) {intptr hbmp = Marshal. stringtohglobalansi (PATH); sendmessage (hwndc, wm_cap_savedib,  0  , Hbmp. toint64 ());}}}