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Invalidate Method

Summary

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

Syntax

C++

public void Invalidate()

  
Public Sub 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.

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(); 
      } 
   } 
}

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

Requirements

Target Platforms

Reference

RasterImageListItem Class

RasterImageListItem Members

Help Version 19.0.2017.10.27

Leadtools.WinForms Assembly

Introduction

Getting Started

Namespaces

Leadtools.WinForms Namespace

Assemblies