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first of all I want to explain what I'm trying to do. I have a ListView in a UserControl with a DataTemplate defined as a resource. I want to hide a button inside the DataTemplate. Sounds easy, but ....
The code I'm using is
&UserControl.Resources&
&DataTemplate x:Key="Proyectos"&
&DockPanel Name="Panel"
Margin="0,0,0,0" MinWidth="1200" MaxWidth="1200"&
&Border Margin="0" BorderBrush="Bisque" BorderThickness="1" DockPanel.Dock="Left"&
&StackPanel Margin="0" Width="1135"&
&DockPanel&
&TextBlock
Text="{Binding titulo}" Name="titulo" FontWeight="Bold" FontSize="12" /&
&/DockPanel&
&DockPanel &
&TextBlock FontWeight="Bold" Text="N? Ref. Fundacion: " DockPanel.Dock="Left" Margin="5,0,5,0" FontSize="11"/&
&TextBlock Name="txb_codproy"
Text="{Binding codproy}" FontSize="11"/&
&TextBlock FontWeight="Bold" Text="
N? Ref. Proyecto: " FontSize="11"/&
&TextBlock Text="{Binding registro}" FontSize="11"/&
&TextBlock FontWeight="Bold" Text="
Estado: " FontSize="11"/&
&TextBlock Text="{Binding estados_proyecto.descripcion}" FontSize="11"/&
&/DockPanel&
&DockPanel &
&TextBlock FontWeight="Bold" Text="Organismo " DockPanel.Dock="Left" Margin="5,0,5,0" FontSize="11"/&
&TextBlock Text="{Binding organismo.descripcion}" FontSize="11"/&
&/DockPanel&
&/StackPanel&
&Border Margin="0" Width="Auto" BorderBrush="Transparent" BorderThickness="1" Background="White" HorizontalAlignment="Left"&
&Button Margin="0,0,0,0" VerticalAlignment="Center" HorizontalAlignment="Left" Name="btn_Eliminar" Click="btn_Eliminar_Click" Width="Auto" Height="25" Background="Transparent" BorderBrush="Transparent"&
&Image Name="img_eliminar" Width="48" Source="imagenes/borrar.png" Height="19" /&
&/DockPanel&
&/DataTemplate&
&/UserControl.Resources&
&Grid Width="1300" Height="845.169"&
&ListView Margin="20,120.024,15.247,50" MouseDoubleClick="list_proyectos_MouseDoubleClick"
Name="list_proyectos" ItemsSource="{Binding}" ItemTemplate="{StaticResource Proyectos}"&
&/ListView&
&TextBox Margin="32,12,35,0" Name="txt_busqueda" TextChanged="textBox1_TextChanged" Background="AliceBlue" BorderBrush="Gray" Height="23" VerticalAlignment="Top" /&
//////////////////////////////////////////////////////////
public Proyectos(IPrincipal identityA)
list_proyectos.ItemsSource = ListaP
list_proyectos.ItemContainerGenerator.StatusChanged += new EventHandler(ItemContainerGenerator_StatusChanged);
void ItemContainerGenerator_StatusChanged(object sender, EventArgs e)
if (list_proyectos.ItemContainerGenerator.Status == System.Windows.Controls.Primitives.GeneratorStatus.ContainersGenerated)
list_proyectos.ItemContainerGenerator.StatusChanged -= ItemContainerGenerator_StatusC
Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Input, new VoidDelegate(DelayedAction));
delegate void VoidDelegate();
void DelayedAction()
foreach (object item in list_proyectos.Items)
ListBoxItem lbitem = (ListBoxItem)list_proyectos.ItemContainerGenerator.ContainerFromItem(item);
if (lbitem != null)
ContentPresenter contentPresenter = FindVisualChild&ContentPresenter&(lbitem);
DataTemplate myDataTemplate = contentPresenter.ContentT
Button b = (Button)lbitem.ContentTemplate.FindName("btn_Eliminar", contentPresenter);
b.Visibility = Visibility.H
private T FindVisualChild&T&(DependencyObject obj)
where T : DependencyObject
for (int i = 0; i & VisualTreeHelper.GetChildrenCount(obj); i++)
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
if (child != null && child is T)
return (T)
for (int i = 0; i & VisualTreeHelper.GetChildrenCount(obj); i++)
DependencyObject child = VisualTreeHelper.GetChild(obj, i);
T childOfChild = FindVisualChild&T&(child);
if (childOfChild != null)
return childOfC
I found two problems with this,
This line (ListBoxItem)list_proyectos.ItemContainerGenerator.ContainerFromItem(item); returns null after the 16th item. The listview has 1576 items
When the ListView is shown and the first 16 items have the button hidden, if I scroll down to the end and then go to top again the buttons are visible again.
14.8k33658
The ListView is using virtualization, therefore it will not have created any containers for items that it knows it doesn't have to display. This is a "good thing", especially considering you have 1576 items.
Perhaps you can explain why you want to be able to get the container for the item that is not visible and we can provide better suggestions as far as what you can do.
28.7k26390
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I'm facing a similar problem with
however VirtualizingStackPanel.IsVirtualizing="False" didn't solve my problem. Is there anyone facing the same issue?
The thing is I have a custom combobox,
&Style TargetType="{x:Type MultiSelectionComboBox}"
&Setter Property="VerticalContentAlignment" Value="Center"/&
&Setter Property="ItemsPanel"&
&Setter.Value&
&ItemsPanelTemplate&
&StackPanel Orientation="Vertical"
VerticalAlignment="Center"
HorizontalAlignment="Center"
VirtualizingStackPanel.IsVirtualizing="False"/&
&/ItemsPanelTemplate&
&/Setter.Value&
&Setter Property="ItemTemplate"&
&Setter.Value&
&DataTemplate&
&StackPanel Orientation="Horizontal" x:Name="ItemStack" VirtualizingStackPanel.IsVirtualizing="False"&
&CheckBox x:Name="CheckBoxItem"
Command="{Binding SelectItem, RelativeSource={RelativeSource AncestorType={x:Type MultiSelectionComboBox}}}"
CommandParameter="{Binding Key}"
&/CheckBox&
&TextBlock Text="{Binding DisplayText}"&&/TextBlock&
&/StackPanel&
&/DataTemplate&
&/Setter.Value&
&Setter Property="Template"&
&Setter.Value&
&ControlTemplate TargetType="{x:Type ComboBox}"&
&Grid x:Name="Placement" SnapsToDevicePixels="true"&
&Grid.ColumnDefinitions&
&ColumnDefinition Width="*"/&
&ColumnDefinition Width="Auto"/&
&/Grid.ColumnDefinitions&
&Border BorderThickness="1" BorderBrush="Black"&
&TextBox IsReadOnly="True" Grid.Column="0"
Text="{Binding Text, UpdateSourceTrigger=PropertyChanged, RelativeSource={RelativeSource AncestorType={x:Type MultiSelectionComboBox}}}"&
&/TextBox&
&Popup x:Name="PART_Popup"
Grid.Column="0"
Focusable="False"
Grid.ColumnSpan="2"
IsOpen="{Binding IsDropDownOpen, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
Placement="Bottom"
VerticalOffset="-1"
PlacementTarget="{Binding ElementName=LayoutRoot}"&
&Popup.Resources&
&Style TargetType="{x:Type ScrollBar}" BasedOn="{StaticResource {x:Type ScrollBar}}"&
&Style.Triggers&
&Trigger Property="Orientation" Value="Vertical"&
&Setter Property="BorderThickness" Value="0"/&
&/Trigger&
&/Style.Triggers&
&/Popup.Resources&
&ScrollViewer x:Name="DropDownScrollViewer"
Background="{StaticResource Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}"
MinWidth="{Binding ActualWidth, ElementName=LayoutRoot}"
MaxHeight="{TemplateBinding MaxDropDownHeight}"&
&ItemsPresenter KeyboardNavigation.DirectionalNavigation="Contained"/&
&/ScrollViewer&
&ToggleButton IsEnabled="{Binding IsEnabled, UpdateSourceTrigger=PropertyChanged, RelativeSource={RelativeSource AncestorType={x:Type MultiSelectionComboBox}}}" Grid.Column="1" IsChecked="{Binding IsDropDownOpen, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Style="{StaticResource ComboBoxToggleButton}"/&
&/ControlTemplate&
&/Setter.Value&
&/ResourceDictionary&
and yet I can't get a reference to the checkbox inside via,
this.ItemContainerGenerator.ContainerFromItem(this.Items[0]) as ComboBoxI
Is there any suggestions?
What i actually want to achieve is,
i want to change checkboxes ischecked property which is depending on an other object which can change on runtime. I can't do it with using bindings due to the current state of the overall project which i can not change at this point. So basically once the new MultiSelectionComboBox is created i want to do something like this,
foreach (object item in this.Items)
ComboBoxItem comboBoxItem = this.ItemContainerGenerator.ContainerFromItem(item) as ComboBoxI
if (comboBoxItem == null)
FrameworkElement element = comboBoxItem.ContentTemplate.LoadContent() as FrameworkE
CheckBox checkBox = element.FindName("CheckBoxItem") as CheckB
checkBox.IsChecked = this.SelectedItem.Contains(item);
try execute UpdateLayout() before this.ItemContainerGenerator.ContainerFromItem(item)
Use ItemContainerGenerator.StatusChanged event from you ComboBox like this:
myComboBox.ItemContainerGenerator.StatusChanged += ItemContainerGenerator_StatusC
void ItemContainerGenerator_StatusChanged(object sender, System.EventArgs e)
if (myComboBox.ItemContainerGenerator.Status == GeneratorStatus.ContainersGenerated)
foreach (var item in myComboBox.Items)
var container = (ComboBoxItem)LanguageComboBox.ItemContainerGenerator.ContainerFromItem(item);
As my logic was in the SelectionChanged event, i wondered why the ItemContainerGenerator.ContainerFromItem method always returned null even if the Listbox.SelectedItem was not null and even more strange, Virtualisation was turned off! Looking at the ItemContainerGenerator.Status i saw that it was Primitives.GeneratorStatus.NotStarted then i added a simple test on ItemContainerGenerator.Status == Primitives.GeneratorStatus.ContainersGenerated and finally solved it that way and no need to subsribe to the Status_Changed event.
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