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# OnMouseButtonUp Method of the IInputEvents Interface

> OnMouseButtonUp method of the IInputEvents Interface in ABBYY FineReader Engine Visual Components on Windows — This method is implemented on the client-side.

This method is implemented on the client-side. It is called by ABBYY FineReader Engine when a mouse button is released in [Image Viewer](/fine-reader/engine/visual-components-reference/imageviewer), [Zoom Viewer](/fine-reader/engine/visual-components-reference/zoomviewer), [Text Editor](/fine-reader/engine/visual-components-reference/texteditor), [Text Validator](/fine-reader/engine/visual-components-reference/textvalidator), or [Document Viewer](/fine-reader/engine/visual-components-reference/documentviewer).

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

## Syntax

### C++

```cpp theme={null}
HRESULT OnMouseButtonUp(
  MouseButtonEnum MouseButton,
  int             Flags,
  int             X,
  int             Y
);
```

### C\#

```csharp theme={null}
void OnMouseButtonUp(
  MouseButtonEnum MouseButton,
  int             Flags,
  int             X,
  int             Y
);
```

### Visual Basic .NET

```vb theme={null}
Sub OnMouseButtonUp( _
  MouseButton As MouseButtonEnum, _
  Flags As Integer, _
  X As Integer, _
  Y As Integer _
)
```

## Parameters

MouseButton

\[in] This variable of the [MouseButtonEnum](/fine-reader/engine/visual-components-reference/enumerations/mousebuttonenum) type specifies the mouse button which is released.

Flags

\[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.

X

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

Y

\[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](/fine-reader/engine/api-reference/return-codes).

## Remarks

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

[IInputEvents](/fine-reader/engine/visual-components-reference/iinputevents)