Windows SDK User Interface: How can I emulate mouse events in an application?

[golanshahar]

Q: How can I emulate mouse events in an application?

A:

• There are two API fucntions that you can use:
  
  
  • 'mouse_event()'.
  • 'SendInput()'.
  
  
  
  
• Which of the two API functions should I use?
  
  The 'mouse_event()' function has been superseded by 'SendInput()' on Window NT/2000/XP. Thus, on these operating systems you should use 'SendInput()' (unless you need to provide backward compatibility with Windows 98 etc.). This FAQ is based on 'SendInput()'.
  
  
  
  
• Can I see some example on how to use 'SendInput()' to emulate a click with the left mouse button?
  
  
  

  void LeftClick ( )
  {  
    INPUT    Input={0};
    // left down 
    Input.type      = INPUT_MOUSE;
    Input.mi.dwFlags  = MOUSEEVENTF_LEFTDOWN;
    ::SendInput(1,&Input,sizeof(INPUT));
  
    // left up
    ::ZeroMemory(&Input,sizeof(INPUT));
    Input.type      = INPUT_MOUSE;
    Input.mi.dwFlags  = MOUSEEVENTF_LEFTUP;
    ::SendInput(1,&Input,sizeof(INPUT));
  }

  
  
• How to use the function?
  
  
  

  LeftClick();

  The left click will be performed on the current position of the mouse cursor.
  
  
  
  
• Can I see some example on how to use 'SendInput()'
  to emulate a click with the right mouse button?
  
  
  

  void RightClick ( )
  {  
    INPUT    Input={0};
    // right down 
    Input.type      = INPUT_MOUSE;
    Input.mi.dwFlags  = MOUSEEVENTF_RIGHTDOWN;
    ::SendInput(1,&Input,sizeof(INPUT));
  
    // right up
    ::ZeroMemory(&Input,sizeof(INPUT));
    Input.type      = INPUT_MOUSE;
    Input.mi.dwFlags  = MOUSEEVENTF_RIGHTUP;
    ::SendInput(1,&Input,sizeof(INPUT));
  }

  
  
• How to use the function?
  
  
  

  RightClick();

  The right click will be performed on the current position of the mouse cursor.
  
  
  
  
• Can I see some example on how to use 'SendInput()' for emulating mouse movement?
  
  
  

  void MouseMove (int x, int y )
  {  
    double fScreenWidth    = ::GetSystemMetrics( SM_CXSCREEN )-1; 
    double fScreenHeight  = ::GetSystemMetrics( SM_CYSCREEN )-1; 
    double fx = x*(65535.0f/fScreenWidth);
    double fy = y*(65535.0f/fScreenHeight);
    INPUT  Input={0};
    Input.type      = INPUT_MOUSE;
    Input.mi.dwFlags  = MOUSEEVENTF_MOVE|MOUSEEVENTF_ABSOLUTE;
    Input.mi.dx = fx;
    Input.mi.dy = fy;
    ::SendInput(1,&Input,sizeof(INPUT));
  }

  
  
• How to use the function?
  
  
  

  MouseMove(100,100);

  This call will move the mouse cursor to the position 100/100 on the screen.

Thanks to cilu for helping writing this FAQ.