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> Fetch the complete documentation index at: https://docs.abbyy.com/llms.txt
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# OnLongOperationFinished Method of the IImageViewerEvents Interface

> OnLongOperationFinished method of the IImageViewerEvents 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 after the end of a long-term processing operation (e.g., layout analysis, recognition) in [Image Viewer](/fine-reader/engine/visual-components-reference/imageviewer). After the operation has been finished, Image Viewer is unlocked. If Image Viewer is connected to Component Synchronizer, the synchronized components locked by Synchronizer before the beginning of this operation are unlocked too.

The method informs the client that a long-term processing operation has been finished. You can use this method to unblock GUI elements of your application after such operations.

## Syntax

### C++

```cpp theme={null}
HRESULT OnLongOperationFinished();
```

### C\#

```csharp theme={null}
void OnLongOperationFinished();
```

### Visual Basic .NET

```vb theme={null}
Sub OnLongOperationFinished()
```

## 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

[IImageViewerEvents](/fine-reader/engine/visual-components-reference/iimageviewerevents)