Develop Reference

C# WPF Disable ListBoxItem Selection in ListBox

I have a ListBox with each ListBoxItem inside containing a label and an image (placed inside border). When I clicked on the image inside ListBoxItem, the ListBoxItem was selected. Is there any possible way to avoid ListBoxItem being selected when clicked on the image (ListBoxItem is allowed to be selected when clicking on the area other than the image).
<ListBox ItemsSource="{Binding SymbolList}" SelectedItem="{Binding SelectedSymbol}" Style="{StaticResource WishlistListBoxStyle}"
HorizontalContentAlignment="Stretch" Width="200" Padding="0">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Label Content="{Binding}" Foreground="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ListBoxItem}}"/>
<Border Grid.Column="1" Visibility="Visible" CornerRadius="5" Height="20" Width="20" Margin="0 0 5 0" HorizontalAlignment="Center" VerticalAlignment="Center">
<Image Height="15" HorizontalAlignment="Center" Source="../Icons/Cross.png"/>
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseDown">
<i:InvokeCommandAction Command="{Binding DataContext.RemoveSymbolCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBox}}}"
CommandParameter="{Binding}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Border.Style>
<Style TargetType="{x:Type Border}">
<Style.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Background" Value="LightGray" />
</Trigger>
</Style.Triggers>
</Style>
</Border.Style>
</Border>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
<Style x:Key="WishlistListBoxStyle" TargetType="{x:Type ListBox}">
<Setter Property="Foreground" Value="White"/>
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="FontSize" Value="15"/>
<Setter Property="FontFamily" Value="Arial"/>
<Setter Property="Background" Value="#282C2F"/>
<Setter Property="ItemContainerStyle">
<Setter.Value>
<Style TargetType="ListBoxItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBoxItem}">
<Border x:Name="WishlistBorder" Style="{DynamicResource WishlistBorderContent}">
<ContentPresenter />
</Border>
<ControlTemplate.Resources>
<Style x:Key="WishlistBorderContent" TargetType="Border">
<Setter Property="BorderThickness" Value="0 0 0 2"/>
<Setter Property="BorderBrush" Value="#50D3D3D3"/>
</Style>
</ControlTemplate.Resources>
<ControlTemplate.Triggers>
<Trigger Property="IsSelected" Value="True">
<Setter TargetName="WishlistBorder" Property="BorderThickness" Value="2"/>
<Setter TargetName="WishlistBorder" Property="BorderBrush" Value="#63C5DA"/>
</Trigger>
<Trigger Property="IsMouseOver" Value="True">
<Setter TargetName="WishlistBorder" Property="Background" Value="#50D3D3D3"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Style>

WPF combobox prevent selection update

I've got a ComboBox that looks like this:
I don't want the value of ... to change when one of the items is selected.
I've tried a ton of different solutions - various bindings on SelectedIndex, SelectedValue, SelectionChanged, playing with IsEditable, IsReadonly, IsHitTestVisible, making ... an actual item, making it placeholder text, etc, etc, etc.
Every time I select an item, the ... updates with the child value. I want it to stay the same.
How can I prevent the combobox from automatically updating the text on selection, but still have it able to select a choice?
If it helps, here's the custom template for that image:
<ResourceDictionary
x:Class="ComboBoxA"
xmlns:local="clr-namespace:MyTemplates"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<ControlTemplate x:Key="ComboBoxA" TargetType="{x:Type ComboBox}">
<Grid>
<ToggleButton
ClickMode="Press"
Focusable="false"
IsChecked="{Binding Path=IsDropDownOpen,Mode=TwoWay,RelativeSource={RelativeSource TemplatedParent}}"
Name="ToggleButton"
>
<ToggleButton.Template>
<ControlTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="36" />
</Grid.ColumnDefinitions>
<Border
x:Name="Border"
Grid.ColumnSpan="2"
CornerRadius="0"
BorderThickness="1" />
<Border
Grid.Column="0"
CornerRadius="0"
Margin="1"
Background="Transparent"
BorderThickness="0"
/>
<Path
x:Name="Arrow"
Grid.Column="1"
Fill="#707070"
HorizontalAlignment="Center"
VerticalAlignment="Center"
Visibility="Collapsed"
Data="M0,0 L8,0 L4,4 z"
/>
<TextBlock
Margin="4,6"
Foreground="#282828"
Grid.Column="0"
Text="{Binding Path=(local:ComboBoxAHelper.Placeholder), RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}"
/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="true">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</Trigger>
<Trigger Property="ToggleButton.IsChecked" Value="true">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</Trigger>
<DataTrigger Binding="{Binding Path=(local:ComboBoxAHelper.ShowBorders), RelativeSource={RelativeSource TemplatedParent}}" Value="True">
<Setter TargetName="Arrow" Property="Visibility" Value="Visible"/>
<Setter TargetName="Border" Property="BorderBrush" Value="#d9d9d9"/>
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</ToggleButton.Template>
</ToggleButton>
<ContentPresenter
Content="{TemplateBinding SelectionBoxItem}"
ContentTemplate="{TemplateBinding SelectionBoxItemTemplate}"
ContentTemplateSelector="{TemplateBinding ItemTemplateSelector}"
HorizontalAlignment="Left"
IsHitTestVisible="False"
Margin="3,3,23,3"
Name="ContentSite"
VerticalAlignment="Center"
/>
<Popup
AllowsTransparency="True"
Focusable="False"
IsOpen="{TemplateBinding IsDropDownOpen}"
Name="Popup"
PopupAnimation="Slide"
>
<Grid Name="DropDown"
MaxHeight="{TemplateBinding MaxDropDownHeight}"
MinWidth="{TemplateBinding ActualWidth}"
SnapsToDevicePixels="True"
>
<Border
Background="White"
BorderBrush="#d9d9d9"
BorderThickness="1"
x:Name="DropDownBorder"
/>
<ScrollViewer Margin="4,6" SnapsToDevicePixels="True">
<StackPanel
IsItemsHost="True"
KeyboardNavigation.DirectionalNavigation="Contained"
/>
</ScrollViewer>
</Grid>
<Popup.Style>
<Style TargetType="Popup">
<Style.Triggers>
<DataTrigger Binding="{Binding Path=(local:ComboBoxAHelper.RightAlignPopup), RelativeSource={RelativeSource TemplatedParent}}" Value="True">
<Setter Property="Placement" Value="Left" />
<Setter Property="VerticalOffset" Value="{Binding ActualHeight, RelativeSource={RelativeSource TemplatedParent}}" />
<Setter Property="HorizontalOffset" Value="{Binding ActualWidth, RelativeSource={RelativeSource TemplatedParent}}" />
</DataTrigger>
</Style.Triggers>
</Style>
</Popup.Style>
</Popup>
</Grid>
</ControlTemplate>
<Style x:Key="ComboBoxAItem" TargetType="{x:Type TextBlock}">
<Setter Property="FontSize" Value="12" />
<Setter Property="Foreground" Value="#282828" />
<Setter Property="Padding" Value="4" />
</Style>
</ResourceDictionary>
...and its corresponding XAML:
<ComboBox
templates:ComboBoxAHelper.Placeholder="..."
templates:ComboBoxAHelper.RightAlignPopup="True"
templates:ComboBoxAHelper.ShowBorders="True"
HorizontalAlignment="Right"
IsReadOnly="True"
IsEditable="False"
SelectedValue="x:Null"
Template="{StaticResource ComboBoxA}"
>
<ComboBoxItem>
<TextBlock Style="{StaticResource ComboBoxAItem}">Close</TextBlock>
</ComboBoxItem>
<ComboBoxItem>
<TextBlock Style="{StaticResource ComboBoxAItem}">Delete</TextBlock>
</ComboBoxItem>
</ComboBox>

The trick was to remove
Content="{TemplateBinding SelectionBoxItem}"
from the template (both in general and also the code posted in the question).
Thanks to #shadow32's answer to my separate question https://stackoverflow.com/a/50805408/385273.

WPF ListBoxItem detect IsMouseOver inside a custom item

i have a ListBox which I fill with custom items. I want to detect a MouseOver event from a ListBoxItem inside the item in order to change visibility of a button. I have checked most of the answers on StackOverflow, the following solution was what I was looking for, but it doesn't work.
This is a code snippet from my ContactsView:
<ListBox ScrollViewer.CanContentScroll="False" VerticalContentAlignment="Top" ScrollViewer.ScrollChanged="ListBox_OnScrollChanged" BorderThickness="0,0,0,0" Margin="0,0,0,0" Padding="0" BorderBrush="{StaticResource ResourceKey=PrimaryColor}" Name="ListBox" ItemsSource="{Binding ListBoxItemsSource}" HorizontalContentAlignment="Stretch">
<i:Interaction.Triggers>
<events:RoutedEventTrigger RoutedEvent="ScrollViewer.ScrollChanged">
<i:InvokeCommandAction Command="{Binding Path=ListBoxScrollChangedCommand}" />
</events:RoutedEventTrigger>
<i:EventTrigger EventName="Loaded">
<i:InvokeCommandAction Command="{Binding Path=ListBoxLoadedCommand}" />
</i:EventTrigger>
</i:Interaction.Triggers>
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="Padding" Value="0"/>
<Setter Property="BorderThickness" Value="0"/>
<Style.Triggers>
<Trigger Property="ListBoxItem.IsMouseOver" Value="True">
<Setter Property="Background" Value="{StaticResource PrimaryColor}"/>
</Trigger>
<Trigger Property="ListBoxItem.IsMouseOver" Value="False">
<Setter Property="Background" Value="Transparent"/>
</Trigger>
</Style.Triggers>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<!-- Custom item -->
<items:ItemCorporateContact Value="{Binding Path=., Mode=TwoWay}" HorizontalAlignment="Stretch" VerticalAlignment="Top" />
<Separator Height="1" Margin="0" Background="#ececec" />
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
And I have been trying to detect the event this way (code from a custom item that I add to a ListBox):
<Button Name="StartCallButton" VerticalAlignment="Center" Background="Red" Margin="10" HorizontalAlignment="Left">
<Button.Content>
<Image Source="{StaticResource PhoneIconBitmap}"></Image>
</Button.Content>
<Button.Style>
<Style TargetType="{x:Type Button}">
<Setter Property="Visibility" Value="Hidden" />
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}},Path=IsMouseOver}" Value="True">
<Setter Property="Visibility" Value="Visible" />
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
Any help will be greatly appreciated.

I had been searching for the same thing. Although the answer is provided in the question, but to specify the answer more clearly, following is the code that works for me.
<ListBox.ItemTemplate>
<DataTemplate>
<StackPanel x:Name="ViewTypeStackPanel" Orientation="Horizontal">
<Border BorderThickness="2,0,0,0" Visibility="{Binding Path=IsSelected, Converter={StaticResource BooleanToVisibilityConverterInstance}}" BorderBrush="Blue"/>
<Image Height="32" Width="32">
<Image.Style>
<Style TargetType="Image">
<Setter Property="Source" Value="{Binding Path=ImagePath}"/>
<Style.Triggers>
<DataTrigger Binding="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type ListBoxItem}}, Path=IsMouseOver}" Value="True">
<Setter Property="Source" Value="{Binding Path=ImagePathHover}"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Image.Style>
</Image>
</StackPanel>
</DataTemplate>
</ListBox.ItemTemplate>

CheckComboBox : How to prevent a combobox from closing after a selection is clicked?

I've got a combobox and it's populated with a bunch of checkboxes. I wish the user to be able to click multiple times before the combobox closes (or is closed by the user themselves). The problems right now is that each time a checkbox is clicked, the combobox closes, forcing the user who wants to select multiple options to re-open it several times.
I've found other questions on the same subject but those apply to Silverlight, Qt etc. comparing the tags.
I've tried setting StayOpenOnEdit but that didn't do the trick. As far I could see, there's no property addressing my issue. That creates a suspicion that I might be barning up the wrong component all together.
How do I prevent the combobox to close automatically after a click in a checkbox in it?
Is there a more suitable component for such task and, if so, what's its name?
Please note that even if the answer to #2 is "yes", I'm still curious of #1 for purely academic reasons.
I've played with toggle button and list box, as someone suggested in a post. However, the that led only to an always fully shown list of all the checkboxes with some greyish thing behind it (which I'm assuming is the toggler). Perhaps I did something less clever in the mark-up.
<ToggleButton HorizontalAlignment="Left"
Margin="550,62,0,0"
VerticalAlignment="Top"
Width="100">
<ListBox x:Name="listBox1"
HorizontalAlignment="Left"
Height="100"
VerticalAlignment="Top" Width="100">
<CheckBox x:Name="checkBox3" Content="CheckBox"/>
<CheckBox x:Name="checkBox4" Content="CheckBox"/>
</ListBox>
</ToggleButton>
The point is to achieve something like this but it needs to be a standard WPF control (the concatenated line of all selected items is nice but not a must). Also, I've read the complaints that the binding and handling is not fully developed yet and I feel a bit suspicious.

Using Exapander Control you can achieve multple item selection without closing popup after single selection.
For understanding please run this code separately.
xaml
<Window.Resources>
<ControlTemplate x:Key="ComboboxToggleButton" TargetType="{x:Type ToggleButton}">
<Grid Background="{Binding Background,RelativeSource={RelativeSource AncestorType={x:Type ComboBox}}}">
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="35" />
</Grid.ColumnDefinitions>
<Border x:Name="Border" Grid.ColumnSpan="2" Background="Transparent" BorderBrush="Black" BorderThickness="{Binding BorderThickness,RelativeSource={RelativeSource TemplatedParent}}"/>
<Path x:Name="Arrow" Grid.Column="1" Opacity="1" Stroke="Black" StrokeThickness="1.5" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 6 6 L 12 0" />
<Path x:Name="Arrow_checked" Opacity="0" Grid.Column="1" Fill="Black" Stroke="Black" StrokeThickness="1" HorizontalAlignment="Center" VerticalAlignment="Center" Data="M 0 0 L 6 6 L 12 0 Z" />
<ContentPresenter TextElement.FontFamily="Segoe Ui Dark" TextElement.FontSize="18" TextElement.Foreground="Black" VerticalAlignment="Center" Grid.Column="0" Margin="10,0,0,0" HorizontalAlignment="Left" RecognizesAccessKey="True" SnapsToDevicePixels="True" />
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsMouseOver" Value="true">
<Setter TargetName="Border" Property="Background" Value="Gray" />
<Setter TargetName="Border" Property="BorderThickness" Value="1.2" />
</Trigger>
<Trigger Property="IsChecked" Value="False">
<Setter Property="Opacity" Value="1" TargetName="Arrow"/>
<Setter Property="Opacity" Value="0" TargetName="Arrow_checked"/>
</Trigger>
<Trigger Property="ToggleButton.IsChecked" Value="true">
<Setter Property="Opacity" Value="0" TargetName="Arrow"/>
<Setter Property="Opacity" Value="1" TargetName="Arrow_checked"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter TargetName="Border" Property="Background" Value="Gray" />
<Setter TargetName="Border" Property="BorderBrush" Value="White" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
<Style TargetType="{x:Type Expander}">
<Setter Property="FontFamily" Value="Segoe Ui Dark"></Setter>
<Setter Property="HorizontalContentAlignment" Value="Stretch"/>
<Setter Property="VerticalContentAlignment" Value="Stretch"/>
<Setter Property="MaxHeight" Value="200"></Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Expander}">
<DockPanel>
<ToggleButton x:Name="HeaderSite" Height="35" Background="{TemplateBinding Background}" ContentTemplate="{TemplateBinding HeaderTemplate}" ContentTemplateSelector="{TemplateBinding HeaderTemplateSelector}" Content="{TemplateBinding Header}" DockPanel.Dock="Top" Foreground="Black" FontStyle="{TemplateBinding FontStyle}" FontFamily="Segoe UI Dark"
IsChecked="{Binding IsExpanded, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}" Template="{StaticResource ComboboxToggleButton}" />
<Border BorderThickness="0,4.5,0,0" BorderBrush="Transparent">
<Border x:Name="bod" BorderBrush="Transparent" SnapsToDevicePixels="True" BorderThickness="1">
<ContentPresenter x:Name="ExpandSite" Focusable="false" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" Visibility="Collapsed" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" />
</Border>
</Border>
</DockPanel>
<ControlTemplate.Triggers>
<Trigger Property="IsExpanded" Value="true">
<Setter Property="Visibility" TargetName="ExpandSite" Value="Visible"/>
<Setter Property="BorderBrush" TargetName="bod" Value="Black"/>
</Trigger>
<Trigger Property="IsEnabled" Value="false">
<Setter Property="Foreground" Value="Gray"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="itemstyle" TargetType="{x:Type ListBoxItem}">
<Setter Property="SnapsToDevicePixels" Value="true" />
<Setter Property="OverridesDefaultStyle" Value="true" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<Grid x:Name="Border" Height="40" SnapsToDevicePixels="true">
<Grid.Background>
<SolidColorBrush Color="Transparent" />
</Grid.Background>
<ContentPresenter Name="cmb_name" TextElement.FontFamily="Segoe Ui Dark" TextElement.FontSize="18" TextElement.Foreground="Black" Margin="10,0,0,0" VerticalAlignment="Center"></ContentPresenter>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter TargetName="Border" Property="Background" Value="Gray"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="FocusVisualStyle">
<Setter.Value>
<Style TargetType="Control">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border BorderBrush="{DynamicResource customBlueBrush}" BorderThickness="1" Margin="1,2,2,2" >
<Rectangle Fill="{DynamicResource customBlueBrush}" Opacity="0.1"></Rectangle>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Style>
<Style TargetType="CheckBox" >
<Setter Property="SnapsToDevicePixels" Value="True"></Setter>
<Setter Property="OverridesDefaultStyle" Value="True"></Setter>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="CheckBox">
<Grid x:Name="ab" Background="Transparent">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="30"/>
<ColumnDefinition/>
</Grid.ColumnDefinitions>
<Rectangle VerticalAlignment="Center" Height="20" Width="20" Fill="White" HorizontalAlignment="Left"></Rectangle>
<Grid x:Name="checkGrid" VerticalAlignment="Center" Height="20" Width="20" Background="Black" HorizontalAlignment="Left">
<Viewbox Height="13" Width="13">
<Path x:Name="Check" SnapsToDevicePixels="True" UseLayoutRounding="True" Width="18.7969" Height="16.3094" Canvas.Left="0" Canvas.Top="1.52588e-005" Stretch="Fill" Fill="White" Data="F1 M 0.731262,8.75935L 0.106262,8.08437C 0.0354614,7.9948 0,7.8979 0,7.79375C 0,7.66875 0.0479736,7.5573 0.143799,7.45937L 1.94067,5.77187C 2.02606,5.69893 2.12708,5.66249 2.24377,5.66249C 2.30212,5.66249 2.36096,5.67397 2.42035,5.69685C 2.47974,5.71977 2.52814,5.75417 2.56567,5.79997L 7.5188,11.1406L 16.0438,0.165604C 16.1417,0.055191 16.2584,1.52588e-005 16.3938,1.52588e-005C 16.4979,1.52588e-005 16.5896,0.0322723 16.6688,0.0968475L 18.6313,1.60939C 18.6709,1.64272 18.7084,1.69011 18.7438,1.75154C 18.7792,1.813 18.7969,1.8698 18.7969,1.92189C 18.7969,2.03435 18.7646,2.1385 18.7,2.23439L 7.74377,16.3094L 0.731262,8.75935 Z " />
</Viewbox>
</Grid>
<Grid Background="Transparent" Grid.Column="1" IsHitTestVisible="True" HorizontalAlignment="Stretch">
<TextBlock VerticalAlignment="Center" FontSize="18" FontFamily="Segoe Ui Dark" Foreground="Black" TextTrimming="CharacterEllipsis">
<ContentPresenter></ContentPresenter>
</TextBlock>
</Grid>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsChecked" Value="True">
<Setter Property="Opacity" Value="1" TargetName="Check"></Setter>
</Trigger>
<Trigger Property="IsChecked" Value="False">
<Setter Property="Opacity" Value="0" TargetName="Check"></Setter>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="FocusVisualStyle">
<Setter.Value>
<Style TargetType="Control">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate>
<Border BorderBrush="{DynamicResource customBlueBrush}" SnapsToDevicePixels="True" BorderThickness="1" Margin="-5,1,3,1" />
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<Grid x:Name="gd" >
<Expander Width="500">
<Expander.Header>
<ListBox Background="Transparent" IsHitTestVisible="False" BorderBrush="Transparent" ScrollViewer.HorizontalScrollBarVisibility="Hidden" ScrollViewer.VerticalScrollBarVisibility="Disabled" BorderThickness="0" ItemsSource="{Binding ElementName=lst,Path=SelectedItems}">
<ListBox.ItemsPanel>
<ItemsPanelTemplate>
<WrapPanel Orientation="Horizontal"></WrapPanel>
</ItemsPanelTemplate>
</ListBox.ItemsPanel>
<ListBox.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding ContentData}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander.Header>
<Expander.Content>
<ListBox Background="Transparent" ItemContainerStyle="{StaticResource itemstyle}" HorizontalContentAlignment="Stretch" x:Name="lst" SelectionMode="Multiple">
<ListBox.ItemTemplate>
<DataTemplate>
<CheckBox x:Name="checkBox" IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBoxItem}}, Path=IsSelected}" Content="{Binding ContentData}"></CheckBox>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Expander.Content>
</Expander>
</Grid>
c# code
public partial class Window1 : Window
{
public Window1()
{
InitializeComponent();
ObservableCollection<Customer> custdata = new ObservableCollection<Customer>();
custdata.Add(new Customer() { ContentData = "content1" });
custdata.Add(new Customer() { ContentData = "content2" });
custdata.Add(new Customer() { ContentData = "content3" });
custdata.Add(new Customer() { ContentData = "content4" });
custdata.Add(new Customer() { ContentData = "content5" });
custdata.Add(new Customer() { ContentData = "content6" });
lst.ItemsSource = custdata;
}
}
public class Customer
{
public string ContentData { get; set; }
}
Result

Konrad,
I also decided to use a ComboBox in this manner, because the code was just dead simple. The easiest way I have found to keep the ComboBox popup open is to wire-up to the PreviewMouseDown event of the control in the ComboBox's item template. handle the behavior yourself, and then mark the mouse event handled. Works great for me. In the sample below, each object in FilterItems is a simple view model with a Text property and an IsChecked property.
<ComboBox IsEditable="True" IsReadOnly="False" ItemsSource="{Binding FilterItems}">
<ComboBox.ItemTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding IsChecked}" Content="{Binding Text}"
PreviewMouseDown="FilterComboBox_PreviewMouseDown"/>
</DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>
And then my event handler is:
private void FilterComboBox_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
var cb = sender as CheckBox;
if (cb != null)
{
cb.IsChecked = !cb.IsChecked;
e.Handled = true;
}
}

How to use a trigger on ToggleButton.IsChecked or IsPressed correctly?

That's my code:
<Window x:Class="WpfTests.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Window.Resources>
<Thickness x:Key="tasksMargin">0,10,0,0</Thickness>
</Window.Resources>
<Grid>
<DockPanel HorizontalAlignment="Left">
<!--<Border Padding="15">-->
<GroupBox>
<GroupBox.Header>
Database Tasks
</GroupBox.Header>
<StackPanel Width="Auto" >
<StackPanel.Resources>
<Style TargetType="RadioButton">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="RadioButton">
<ToggleButton IsChecked="{Binding IsChecked, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
Content="{Binding Content, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
BorderThickness="2" BorderBrush="Yellow" Background="White"/>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsChecked" Value="True">
<Setter Property="Content" Value="different txt" />
</Trigger>
<Trigger Property="ToggleButton.IsPressed" Value="True">
<Setter Property="Content" Value="different text" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="Margin" Value="5">
</Setter>
</Style>
</StackPanel.Resources>
<RadioButton GroupName="Group1" x:Name="button1">Option1</RadioButton>
<RadioButton GroupName="Group1" x:Uid="button2" x:Name="button2">button2</RadioButton>
<RadioButton GroupName="Group1" x:Uid="button3" x:Name="button3">button3</RadioButton>
</StackPanel>
</GroupBox>
</DockPanel>
</Grid>
However, the IsChecked and IsPressed triggers do not get triggered. how to I declare them properly?

If you give your ToggleButton a name and then reference that in the trigger setters then it should work. So, your ControlTemplate would look something like...
<ControlTemplate TargetType="RadioButton">
<ToggleButton Name="toggleButton" IsChecked="{Binding IsChecked, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
Content="{Binding Content, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
BorderThickness="2" BorderBrush="Yellow" Background="White"/>
<ControlTemplate.Triggers>
<Trigger Property="ToggleButton.IsChecked" Value="True">
<Setter TargetName="toggleButton" Property="Content" Value="different txt" />
</Trigger>
<Trigger Property="ToggleButton.IsPressed" Value="True">
<Setter TargetName="toggleButton" Property="Content" Value="different text" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>

The prefixed types in the triggers are not needed, also change the bindings on the togglebutton to TemplateBindings.

There some other solutions available, but for this problem. Do the following:
1) Give Your Toggle Name
<ToggleButton Name="tglBtn" IsChecked="{Binding IsChecked, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
Content="{Binding Content, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
BorderThickness="2" BorderBrush="Yellow" Background="White"/>
2) In trigger reference by the name given
<Trigger SourceName="tglBtn" Property="IsChecked" Value="True">
<Setter TargetName="tglBtn" Property="Content" Value="different txt" />
</Trigger>
Hope that helps