OnMouseButtonDown Method of the IInputEvents Interface

This method is implemented on the client-side. It is called by ABBYY FineReader Engine when a mouse button is pressed in Image Viewer, Zoom Viewer, Text Editor, Text Validator, or Document Viewer.

It delivers to the client information on the mouse button which is pressed, and the coordinates of the mouse pointer.



HRESULT OnMouseButtonDown(
  MouseButtonEnum MouseButton,
  int             Flags,
  int             X,
  int             Y


void OnMouseButtonDown(
  MouseButtonEnum MouseButton,
  int             Flags,
  int             X,
  int             Y

Visual Basic .NET

Sub OnMouseButtonDown( _
  MouseButton As MouseButtonEnum, _
  Flags As Integer, _
  X As Integer, _
  Y As Integer _


[in] This variable of the MouseButtonEnum type specifies the mouse button which is pressed.
[in] Indicates whether various virtual keys are down. This parameter can be any combination of the following values:
  • MK_CONTROL (0x0008), if Ctrl key is down.
  • MK_LBUTTON (0x0001), if left mouse button is down.
  • MK_MBUTTON (0x0010), if middle mouse button is down.
  • MK_RBUTTON (0x0002), if right mouse button is down.
  • MK_SHIFT (0x0004), if Shift key is down.

The constants are defined in Winuser.h.

[in] Specifies the horizontal coordinate of the mouse pointer in screen coordinates.
[in] Specifies the vertical coordinate of the mouse pointer in screen coordinates.

Return values

This method has no specific return values. It returns the standard return values of ABBYY FineReader Engine functions.


The client implementation of this method must assure that all exceptions thrown inside the method are caught and handled and no exceptions are propagated outside the method. Propagation of an exception outside the method may lead to unpredictable results (such as program termination).

See also


24.03.2023 8:51:52

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