Invalidate Method

Redraws the item and causes a paint message to be sent to the RasterImageList control that owns this item.

Syntax

C#
Visual Basic
Objective-C
Java
C++

public void Invalidate()

'Declaration
 
Public Sub Invalidate()

'Usage
 
Dim instance As RasterImageListItem
 
instance.Invalidate()

public:
void Invalidate();

Remarks

You can call Invalidate after you make changes to a certain RasterImageListItem that belongs to a RasterImageList control. Calling Invalidate on the item causes only the portion of the control covered with the item to be invalidated as apposed to invalidating the surface of the entire control.

Example

This example shows how to manually select an item in a RasterImageListItem while updating only the affected area.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Imports Leadtools.WinForms
Imports Leadtools
Imports Leadtools.Codecs

''' 
Private Sub SelectImageListItem(ByVal imageList As RasterImageList, ByVal itemIndex As Integer)
   ' Loop through all the items in the list
   Dim i As Integer = 0
   Do While i < imageList.Items.Count
      Dim item As RasterImageListItem = imageList.Items(i)
      ' If this is not out item and is selected, de-select it
      If i <> itemIndex AndAlso item.Selected Then
         item.Selected = False

         ' re-paint only this item
         item.Invalidate()
      End If

      ' If this is our item and is not selected already, select it
      If i = itemIndex AndAlso (Not item.Selected) Then
         item.Selected = True

         ' re-paint only this item
         item.Invalidate()
      End If
      i += 1
   Loop
End Sub

using Leadtools.WinForms;
using Leadtools;
using Leadtools.Codecs;

/// 
private void SelectImageListItem(RasterImageList imageList, int itemIndex)
{
   // Loop through all the items in the list
   for (int i = 0; i < imageList.Items.Count; i++)
   {
      RasterImageListItem item = imageList.Items[i];
      // If this is not out item and is selected, de-select it
      if (i != itemIndex && item.Selected)
      {
         item.Selected = false;

         // re-paint only this item
         item.Invalidate();
      }

      // If this is our item and is not selected already, select it
      if (i == itemIndex && !item.Selected)
      {
         item.Selected = true;

         // re-paint only this item
         item.Invalidate();
      }
   }
}

Requirements

Target Platforms

Reference

RasterImageListItem Class
RasterImageListItem Members