I have implemented below mentioned code in WPF in that I have implemented virtualization of lazy loading but it's not work when my inner collection have a 1000 of record then it will take much time to load on screen.
<ListBox x:Name="Mappingcontrol" Grid.Row="1"
DataContext="{Binding ElementName=Grids,Path=DataContext}"
VerticalAlignment="Stretch" HorizontalAlignment="Stretch"
ItemsSource="{Binding Path=MultiMappingCollectionList, Mode=TwoWay}"
VirtualizingStackPanel.IsVirtualizing="True"
VirtualizingStackPanel.VirtualizationMode="Recycling"
BorderThickness="0" BorderBrush="Transparent"
Background="Transparent"
HorizontalContentAlignment="Stretch"
VerticalContentAlignment="Stretch"
ItemContainerStyle="{StaticResource TransparentListBoxStyle}">
<ListBox.ItemTemplate>
<DataTemplate>
<Border Padding="0,10,0,10" BorderThickness="0,0,0,1"
BorderBrush="{StaticResource Gray5SolidBrush}">
<Grid x:Name="Gridmain" Margin="4,0,0,0">
<Grid.ColumnDefinitions>
<ColumnDefinition x:Name="default" Width="0.5*" SharedSizeGroup="default" />
<ColumnDefinition x:Name="atrioValue" Width="1*"
SharedSizeGroup="atrioValue" />
<ColumnDefinition x:Name="externalValue" Width="2*"
SharedSizeGroup="externalValue" />
</Grid.ColumnDefinitions>
<ToggleButton VerticalAlignment="Top"
HorizontalAlignment="Left"
Style="{DynamicResource ToggleButtonStyle}"
Margin="30,12,10,10" IsTabStop="False" Width="25"
Height="25"
IsChecked="{Binding IsDefault, Mode=TwoWay}">
<TextBlock Grid.Column="1" Margin="0,15,10,10" HorizontalAlignment="Left"
VerticalAlignment="Top"
Text="{Binding Path=Description}"
Style="{StaticResource ContentDataText}"
Name="txtDescription" />
<ListBox x:Name="GroupListBox" Grid.Column="2"
ItemsSource="{Binding Path=MultiMapping,Mode=TwoWay}"
HorizontalContentAlignment="Stretch"
BorderThickness="0"
BorderBrush="Transparent"
Background="Transparent"
VerticalContentAlignment="Stretch"
VirtualizingStackPanel.IsVirtualizing="True"
VirtualizingStackPanel.VirtualizationMode="Recycling"
VirtualizingStackPanel.CacheLength="2,3"
VirtualizingStackPanel.CacheLengthUnit="Page"
ItemContainerStyle="{StaticResource TransparentListBoxStyle}">
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Horizontal" CanVerticallyScroll="True" Height="200">
<telerik:RadWatermarkTextBox x:Name="ExternalValueTextBox"
HorizontalAlignment="Left"
TabIndex="100"
KeyboardNavigation.TabIndex="100"
IsTabStop="True"
Width="250"
MaxLength="35"
TextWrapping="Wrap"
Validation.ErrorTemplate="{DynamicResource CustomErrorTemplate}"
Text="{Binding Path=ExternalValue, Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
PreviewTextInput="ExternalValueTextBox_OnPreviewTextInput"
Style="{DynamicResource RadWatermarkTextBoxDefault}"
Visibility="{Binding Path=ExternalValue,Converter={StaticResource StarVisibilityConverter}}"
Margin="0,5,0,0">
</telerik:RadWatermarkTextBox>
<Button x:Name="DeleteButton" Background="Transparent"
BorderThickness="0"
BorderBrush="Transparent"
CommandParameter="{Binding}"
Command="{Binding DataContext.RemoveGrouplistCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}}"
HorizontalAlignment="Right"
VerticalAlignment="Center"
Visibility="{Binding Path=RemoveButtonVisibility,Converter={StaticResource BooleanHiddenVisibleConverter},Mode=TwoWay}"
Margin="15,5,15,0"
Style="{DynamicResource ButtonInvisibleNoColorEffects}">
<Button.Content>
<Rectangle Style="{StaticResource SmallCloseIcon}" />
</Button.Content>
</Button>
<Grid x:Name="AddGrid"
Visibility="{Binding Path=AddbuttonVisibility,Converter={StaticResource BooleanVisibilityConverter}}">
<controls:ActionImageButton x:Name="AddButton"
Content="Add Another"
DataContext="{Binding ElementName=Root,Path=DataContext}"
CommandParameter="{Binding ElementName=txtDescription,Path=Text}"
Command="{Binding AddGrouplistCommand}"
HorizontalAlignment="Right"
VerticalAlignment="Center"
IsEnabled="{Binding ElementName=ExternalValueTextBox,Path=Text,Converter={StaticResource StarVisibilityConverter},ConverterParameter=CanAdd}"
Margin="5,5,30,5"
Style="{StaticResource ActionImageButtonMedium}" />
</Grid>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
</Border>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
It would be great help if anyone can light on me what's I am doing wrong in it Thanks in advance.
