GdPicture.NET Reference Guide
DisplayPreviousPage() Method
Example 





GdPicture14.WPF Namespace > GdViewer Class : DisplayPreviousPage() Method
Displays the previous page, if any is available, of the document currently loaded in the GdViewer control. You can use the CurrentPage property to determine the currently displayed page.

The PageDisplayed and the PageChanged events, respectively the PreviewPageDisplayed and the PreviewPageChanged events, are raised after the page has been successfully displayed and changed.

Be aware that the SaveAnnotationsToPage method is called internally before each page change.

Syntax
'Declaration
 
Public Function DisplayPreviousPage() As GdPictureStatus
public GdPictureStatus DisplayPreviousPage()
public function DisplayPreviousPage(): GdPictureStatus; 
public function DisplayPreviousPage() : GdPictureStatus;
public: GdPictureStatus DisplayPreviousPage(); 
public:
GdPictureStatus DisplayPreviousPage(); 

Return Value

A member of the GdPictureStatus enumeration. If the method has been successfully followed, then the return value is GdPictureStatus.OK. We strongly recommend always checking this status first.
Remarks
Please note that if no previous page is available, this method does nothing.

Just to remind you that both the PageDisplayed and the PageChanged events, respectively the PreviewPageDisplayed and the PreviewPageChanged events, are raised using this method.

Example
How to introduce the page browsing feature in your viewer.
'We assume that the GdViewer1 control has been properly integrated
'and your document has been properly displayed as well.
Enum Direction
    FirstP
    LastP
    NextP
    PreviousP
End Enum
Sub DoMove(ByVal MoveTo As Direction)
    Dim status As GdPictureStatus = GdPictureStatus.OK
    Select Case MoveTo
        Case Direction.FirstP
            status = GdViewer1.DisplayFirstPage()
        Case Direction.LastP
            status = GdViewer1.DisplayLastPage()
        Case Direction.NextP
            status = GdViewer1.DisplayNextPage()
        Case Direction.PreviousP
            status = GdViewer1.DisplayPreviousPage()
        Case Else
    End Select
    If status <> GdPictureStatus.OK Then MessageBox.Show("Failure: " + status.ToString(), "GdViewer.DisplayPreviousPage")
End Sub
//We assume that the GdViewer1 control has been properly integrated
//and your document has been properly displayed as well.
enum Direction { FirstP, LastP, NextP, PreviousP };
void DoMove(Direction MoveTo)
{
    GdPictureStatus status = GdPictureStatus.OK;
    switch (MoveTo)
    {
        case Direction.FirstP: status = GdViewer1.DisplayFirstPage(); break;
        case Direction.LastP: status = GdViewer1.DisplayLastPage(); break;
        case Direction.NextP: status = GdViewer1.DisplayNextPage(); break;
        case Direction.PreviousP: status = GdViewer1.DisplayPreviousPage(); break;
        default: break;
    }
    if (status != GdPictureStatus.OK) MessageBox.Show("Failure: " + status.ToString(), "GdViewer.DisplayPreviousPage");
}
See Also

Reference

GdViewer Class
GdViewer Members
CurrentPage Property
PageCount Property
DisplayPage(Int32) Method
DisplayNextPage Method
PageDisplayed Event
PageChanged Event
SaveAnnotationsToPage Method