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EnsureVisible Method

Summary

Ensures that the specified item is visible within the control, scrolling the contents of the control if necessary.

Syntax

C++

public void EnsureVisible( 
   int index 
)

  
Public Sub EnsureVisible( _ 
   ByVal index As Integer _ 
)

public: 
void EnsureVisible(  
   int index 
)

Parameters

index
The zero-based index of the item to scroll into view.

Remarks

You can use this method to ensure that a specific item is visible within the RasterImageList control. When performing validation on the items in a RasterImageList, you can call the EnsureVisible method to ensure that an item that failed validation is displayed in the RasterImageList control to allow the user to perform changes on the item. If the item that you want to ensure is visible is located above the viewable region of the RasterImageList control, calling the EnsureVisible method will scroll the contents of the control until it is the first item in the viewable area of the control. If the item is below the viewable region of the RasterImageList control, calling the EnsureVisible method will scroll the contents of the RasterImageList control until the item is the last item in the viewable area of the control.

To determine if an item is located at the top of the display area of a RasterImageList control, use the TopIndex property.

Example

This example will add a new item to the end of a RasterImageList control and make sure the item is visible to the user.

using Leadtools.WinForms; 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.Drawing; 
 
public void RasterImageList_EnsureVisible(RasterImageList imageList) 
{ 
   RasterCodecs codecs = new RasterCodecs(); 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "image1.cmp")); 
 
   imageList.ScrollStyle = RasterImageListScrollStyle.Horizontal; 
 
   // Append the new item to the image list control 
   RasterImageListItem item = new RasterImageListItem(image, 1, "New Item"); 
   imageList.Items.Add(item); 
   int nIndex = imageList.Items.IndexOf(item); 
 
   // Make sure this new item is visible to the user 
   imageList.EnsureVisible(nIndex); 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
}

Imports Leadtools.WinForms 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.Drawing 
 
Public Sub RasterImageList_EnsureVisible(ByVal imageList As RasterImageList) 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   Dim image As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "image1.cmp")) 
 
   imageList.ScrollStyle = RasterImageListScrollStyle.Horizontal 
 
   ' Append the new item to the image list control 
   Dim item As RasterImageListItem = New RasterImageListItem(image, 1, "New Item") 
   imageList.Items.Add(item) 
   Dim nIndex As Integer = imageList.Items.IndexOf(item) 
 
   ' Make sure this new item is visible to the user 
   imageList.EnsureVisible(nIndex) 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class

Requirements

Target Platforms

Reference

RasterImageList Class

RasterImageList Members

Help Version 19.0.2017.10.27