OnActivePageChanging Method of the IDocumentViewerEvents Interface

OnActivePageChanging method of the IDocumentViewerEvents 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 before changing the active page in Document Viewer. The process is invoked if the page is changed via the graphical user interface of Document Viewer or any synchronized component. The process is not invoked if the active page is changed via API of Document Viewer or if the active page has been deleted.

The method delivers to the client a reference to the new active page. With the help of this method it is possible to cancel the operation.

Syntax

C++

HRESULT OnActivePageChanging(
  IFRPage*      Page,
  VARIANT_BOOL* Cancel
);

C#

void OnActivePageChanging(
  IFRPage   Page,
  out bool Cancel
);

Visual Basic .NET

Sub OnActivePageChanging( _
  Page As IFRPage, _
  ByRef Cancel As Boolean _
)

Parameters

Page

[in] Refers to the FRPage object which contains the new active page. This parameter may be NULL, which means that there is no active page in the document (for example, if all pages have been deleted).

Cancel

[out] You may set this variable to TRUE to indicate that the process should be terminated. In this case, the active page will not be changed.

Return values

[C++ only] If this method returns a value other than S_OK, it indicates that an error occurred on the client-side, and in this case the value of the Cancel parameter is not taken into account.

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

IDocumentViewerEvents