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PageNumber Property (ImageViewerItem)

Summary

Page number to use if Image has more than one page (frame).

Syntax

C++

public int PageNumber { get; set; }

Public Property PageNumber() As Integer 
   Get 
   Set

public:  
   property int PageNumber 
   { 
      int get() 
      void set(int value) 
   }

Property Value

The 1-based page number to use by this item of Image has more than one page. Default value is 0.

Remarks

This value is used as the 1-based page number when a valid object is set in the Image property. RasterImage supports multi-page images (frames) and the same value can be set in multiple items. Use PageNumber to control which page is used by the item.

Note that even through the default value of 0 is not a legal page number, the item will check and internally revert to using 1 (first page).

ImageViewerPagerInteractiveMode uses the value of this property to cycle through the pages of a multi-page image in an item.

For more information, refer to Image Viewer Items.

Example

using Leadtools; 
using Leadtools.Controls; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
using LeadtoolsExamples.Common; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Color; 
 
if (_imageViewer.Items.Count > 0) 
{ 
   var item = _imageViewer.ActiveItem; 
   var image = item != null ? item.Image : null; 
   var pageCount = (image != null) ? image.PageCount : 1; 
 
   if (pageCount > 1) 
   { 
      var oldPageNumber = item.PageNumber; 
      var newPageNumber = oldPageNumber; 
 
      if (_previousItem) 
         newPageNumber--; 
      else 
         newPageNumber++; 
 
      newPageNumber = Math.Max(1, Math.Min(pageCount, newPageNumber)); 
      if (newPageNumber != oldPageNumber) 
      { 
         item.PageNumber = newPageNumber; 
      } 
   } 
   else 
   { 
      var index = _imageViewer.Items.IndexOf(_imageViewer.ActiveItem); 
      if (_previousItem) 
         index--; 
      else 
         index++; 
 
      if (index >= 0 && index < _imageViewer.Items.Count) 
         _imageViewer.ActiveItem = _imageViewer.Items[index]; 
   } 
}

Imports Leadtools 
Imports Leadtools.Controls 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Color 
Imports LeadtoolsControlsExamples.LeadtoolsExamples.Common 
 
If _imageViewer.Items.Count > 0 Then 
   Dim item As ImageViewerItem = _imageViewer.ActiveItem 
   Dim image As RasterImage 
   If Not item Is Nothing Then 
      image = item.Image 
   Else 
      image = Nothing 
   End If 
   Dim pageCount As Integer 
   If (Not image Is Nothing) Then 
      pageCount = image.PageCount 
   Else 
      pageCount = 1 
   End If 
 
   If pageCount > 1 Then 
      Dim oldPageNumber As Integer = item.PageNumber 
      Dim newPageNumber As Integer = oldPageNumber 
 
      If _previousItem Then 
         newPageNumber -= 1 
      Else 
         newPageNumber += 1 
      End If 
 
      newPageNumber = Math.Max(1, Math.Min(pageCount, newPageNumber)) 
      If newPageNumber <> oldPageNumber Then 
         item.PageNumber = newPageNumber 
      End If 
   Else 
      Dim index As Integer = _imageViewer.Items.IndexOf(_imageViewer.ActiveItem) 
      If _previousItem Then 
         index -= 1 
      Else 
         index += 1 
      End If 
 
      If index >= 0 AndAlso index < _imageViewer.Items.Count Then 
         _imageViewer.ActiveItem = _imageViewer.Items(index) 
      End If 
   End If 
End If

Requirements

Target Platforms

Reference

ImageViewerItem Class

ImageViewerItem Members

Leadtools.Controls Namespace