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How to persistently change color of ListBox SelectedItem after selecting

I have a listbox that loads it's items with Foreground color set to red. What I'd like to do is: upon selecting an item with the mouse, change the foreground color of SelectedItem to black, but make the change persistent so that after deselecting the item, color remains black. Incidentally I want to implement this as a way of showing 'read items' to the user.
Essentially I want something like an implementation of the common property trigger like the code below, but not have the style revert after deselection. I've played around with event triggers as well without much luck.
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Style.Triggers>
<Trigger Property="IsSelected" Value="True" >
<Setter Property="Foreground" Value="Black" /> //make this persist after deselection
</Trigger>
</Style.Triggers>
</Style>
</ListBox.ItemContainerStyle>
Thanks in advance!

You could animate the Foreground property:
<ListBox>
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="Foreground" Value="Red" />
<Style.Triggers>
<Trigger Property="IsSelected" Value="True">
<Trigger.EnterActions>
<BeginStoryboard>
<Storyboard>
<ColorAnimation Storyboard.TargetProperty="(ListBoxItem.Foreground).(SolidColorBrush.Color)"
To="Black" />
</Storyboard>
</BeginStoryboard>
</Trigger.EnterActions>
</Trigger>
</Style.Triggers>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
The downside of this simple approach is that the information is not stored somewhere. This is pure visualization without any data backing. In order to persist the information, so that restarting the application shows the same previous state, you should introduce a dedicated property to your data model e.g IsMarkedAsRead.
Depending on your requirements, you can override the ListBoxItem.Template and bind ToggleButton.IsChecked to IsMarkedAsRead or use a Button which uses a ICommand to set the IsMarkedAsRead property. There are many solutions e.g. implementing an Attached Behavior.
The following examples overrides the ListBoxItem.Template to turn the ListBoxItem into a Button. Now when the item is clicked the IsMarkedAsRead property of the data model is set to true:
Data model
(See Microsoft Docs: Patterns - WPF Apps With The Model-View-ViewModel Design Pattern for an implementation example of the RelayCommand.)
public class Notification : INotifyPropertyChanged
{
public string Text { get; set; }
public ICommand MarkAsReadCommand => new RelayCommand(() => this.IsMarkedAsRead = true);
public ICommand MarkAsUnreadCommand => new RelayCommand(() => this.IsMarkedAsRead = false);
private bool isMarkedAsRead;
public bool IsMarkedAsRead
{
get => this.isMarkedAsRead;
set
{
this.isMarkedAsRead = value;
OnPropertyChanged();
}
}
#region INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
ListBox
<ListBox ItemsSource="{Binding Notifications}">
<ListBox.ItemContainerStyle>
<Style TargetType="ListBoxItem">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<Border Background="{TemplateBinding Background}">
<Button x:Name="ContentPresenter"
ContentTemplate="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=ListBox}, Path=ItemTemplate}"
Content="{TemplateBinding Content}"
Command="{Binding MarkAsReadCommand}"
Foreground="Red">
<Button.Template>
<ControlTemplate TargetType="Button">
<Border>
<ContentPresenter />
</Border>
</ControlTemplate>
</Button.Template>
</Button>
</Border>
<ControlTemplate.Triggers>
<DataTrigger Binding="{Binding IsMarkedAsRead}" Value="True">
<Setter TargetName="ContentPresenter" Property="Foreground" Value="Green" />
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.ItemContainerStyle>
<ListBox.ItemTemplate>
<DataTemplate DataType="{x:Type Notification}">
<TextBlock Text="{Binding Text}"/>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>

Thanks a lot #BionicCode for the comprehensive answer. I ended up going with another solution which may or may not be good convention; I am a hobbyist.
Firstly, I don't need databacking / persistence.
Concerning the data model solution and overriding ListBoxItem.Template, I am using a prededfined class 'SyndicationItem' as the data class (my app is Rss Reader). To implement your datamodel solution I guess I could hack an unused SyndicationItem property, or use SyndicationItem inheritance for a custom class (I'm guessing this is the most professional way?)
My complete data model is as follows:
ObservableCollection >>> CollectionViewSource >>> ListBox.
Anyway I ended up using some simple code behind which wasn't so simple at the time:
First the XAML:
<Window.Resources>
<CollectionViewSource x:Key="fooCollectionViewSource" Source="{Binding fooObservableCollection}" >
<CollectionViewSource.SortDescriptions>
<scm:SortDescription PropertyName="PublishDate" Direction="Descending" />
</CollectionViewSource.SortDescriptions>
</CollectionViewSource>
<Style x:Key="DeselectedTemplate" TargetType="{x:Type ListBoxItem}">
<Setter Property="Foreground" Value="Gray" />
</Style>
</Window.Resources>
<ListBox x:Name="LB1" ItemsSource="{Binding Source={StaticResource fooCollectionViewSource}}" HorizontalContentAlignment="Stretch" Margin="0,0,0,121" ScrollViewer.HorizontalScrollBarVisibility="Disabled" >
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="80" />
</Grid.ColumnDefinitions>
<TextBlock MouseDown="TextBlock_MouseDown" Grid.Column="0" Text="{Binding Path=Title.Text}" TextWrapping="Wrap" FontWeight="Bold" />
<TextBlock Grid.Column="1" HorizontalAlignment="Right" TextAlignment="Center" FontSize="11" FontWeight="SemiBold"
Text="{Binding Path=PublishDate.LocalDateTime, StringFormat='{}{0:d MMM, HH:mm}'}"/>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
Now the code behind:
Solution 1: this applies a new style when listboxitem is deselected. Not used anymore so the LB1_SelectionChanged event is not present in the XAML.
private void LB1_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
if (e.RemovedItems.Count != 0)
{
foreach (var lbItem in e.RemovedItems)
{
//get reference to source listbox item. This was a pain.
int intDeselectedItem = LB1.Items.IndexOf(lbItem);
ListBoxItem lbi = (ListBoxItem)LB1.ItemContainerGenerator.ContainerFromIndex(intDeselectedItem);
/*apply style. Initially, instead of applying a style, I used mylistboxitem.Foreground = Brushes.Gray to set the text color.
Howver I noticed that if I scrolled the ListBox to the bottom, the text color would revert to the XAML default style in my XAML.
I assume this is because of refreshes / redraws (whichever the correct term). Applying a new style resolved.*/
Style style = this.FindResource("DeselectedTemplate") as Style;
lbi.Style = style;
}
}
}
Solution 2: The one I went with. Occurs on SelectedItem = true, same effect as your first suggestion.
private void TextBlock_MouseDown(object sender, MouseButtonEventArgs e)
{
TextBlock tb = e.Source as TextBlock;
tb.Foreground = Brushes.Gray;
}

UWP style trigger missing

It seems that UWP XAML doesn't support triggers in styles. What is the common workaround to accomplish triggers like the following?
<Style TargetType="Button">
<Style.Triggers>
<Trigger Property="Visibility" Value="Collapsed">
<Setter Property="Text" Value="" />
</Trigger>
</Style.Triggers>
</Style>
At the moment I see the following options to accomplish triggers in UWP:
Use Animations or VisualStateTriggers. Both seem to be wrong if I use them not to adjust the controls to the screen.
I think I found the correct way to implement Triggers in general for Controls.
See the below code as demonstration:
xmlns:Interactivity="using:Microsoft.Xaml.Interactivity"
xmlns:Core="using:Microsoft.Xaml.Interactions.Core"
<Border x:Name="BackgroundElement" Tag="Text">
<Interactivity:Interaction.Behaviors>
<Core:DataTriggerBehavior Binding="{Binding Tag, ElementName=BackgroundElement}" Value="Text">
<Core:ChangePropertyAction PropertyName="BorderBrush" Value="AliceBlue" />
</Core:DataTriggerBehavior>
</Interactivity:Interaction.Behaviors>
</Border>
It would be awesome if there is a solution without ElementName. I would have done this in WPF with AncestorType, but that's missing in UWP too. Anyway, it seems that you can't use the Core:DataTriggerBehavior in styles.

In WinRT, RelativeSourceMode only support Self and TemplatedParent mode, FindAncestor is not available. So when you use XAML Behaviors, you need to use ElementName as a workaround. And if you are using DataContext or ViewModel in your project, you can bind to the DataContext or ViewModel to avoid using ElementName. For example:
<Page ...>
<Page.Resources>
<local:MyViewModel x:Key="ViewModel" />
</Page.Resources>
...
<Border x:Name="BackgroundElement" DataContext="{Binding Source={StaticResource ViewModel}}">
<Interactivity:Interaction.Behaviors>
<Core:DataTriggerBehavior Binding="{Binding Tag}" Value="Text">
<Core:ChangePropertyAction PropertyName="Background" Value="Red" />
</Core:DataTriggerBehavior>
</Interactivity:Interaction.Behaviors>
</Border>
...
</Page>
And the ViewModel used above:
public class MyViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private string _tag;
public string Tag
{
get
{
return _tag;
}
set
{
_tag = value;
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs("Tag"));
}
}
}
}

WPF ListBoxItem ControlTemplate breaks some MouseDown/Selection

I have an issue with ListBoxItems. I am trying to make all controls in the ListBoxItem select it as well, so clicking on a TextBox, Label, etc will select the ListBoxItem. Pretty simple so far.
I am also changing the ListBoxItem Template to change the selection visualization from highlighting the background to just drawing a border. Also pretty simple.
The combination of these two, however, seems to cause some really irritating issues with MouseDown and PreviewMouseDown, specifically in my case regarding Labels in a Grid, where one creates a "void" occupied by Grid space.
Using snoop, I can see the PreviewMouseDown event stopping at the ScrollViewer inside the ListBox, and not going all the way to the ListBoxItem.
XAML:
<Window x:Class="ListBoxClickThroughTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Width="525"
Height="350">
<Grid>
<ListBox ItemsSource="{Binding Items}"
SelectionMode="Single">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<Label Name="VerySuperLongLabel"
Grid.Row="0"
Grid.Column="0"
HorizontalAlignment="Left"
Content="VerySuperLongLabel"
Padding="0" />
<TextBox Name="Textbox1"
Grid.Row="0"
Grid.Column="1"
HorizontalAlignment="Stretch"
HorizontalContentAlignment="Right"
Text="Textbox1 Text" />
<Label Name="ShortLabel"
Grid.Row="1"
Grid.Column="0"
HorizontalAlignment="Left"
Content="ShortLabel"
Padding="0" />
<TextBox Name="Textbox2"
Grid.Row="1"
Grid.Column="1"
HorizontalAlignment="Stretch"
HorizontalContentAlignment="Right"
Text="Textbox2 Text" />
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<EventSetter Event="PreviewMouseDown"
Handler="ListBoxItem_PreviewMouseDown" />
<EventSetter Event="MouseDown"
Handler="ListBoxItem_PreviewMouseDown" />
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBoxItem}">
<Border x:Name="Bd"
BorderThickness="1">
<ContentPresenter />
</Border>
<ControlTemplate.Triggers>
<Trigger Property="IsSelected" Value="true">
<Setter TargetName="Bd" Property="BorderBrush" Value="Gray" />
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
</Grid>
</Window>
Code-behind:
using System.Collections.Generic;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
namespace ListBoxClickThroughTest
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
Items = new List<string>() { "1", "2" };
InitializeComponent();
DataContext = this;
}
public List<string> Items { get; set; }
private void ListBoxItem_PreviewMouseDown(object sender, MouseButtonEventArgs e)
{
var listBoxItem = (ListBoxItem)sender;
listBoxItem.IsSelected = true;
}
}
}
However, if I remove the Template setter, all is well. Is there some magic in the template I'm missing? I tried renaming the border to "Bd" as that was what the default template border was named, but no luck. Any ideas?

If you change the horizontal alignment of the labels from "Left" to "Stretch" this will fix the problem and keep the visual formatting the same.
Mousedown events only work in areas where elements exist. By having the labels at a "left" horizontal alignment, you are creating the "void" you mentioned, where no element exists at that level that can be clicked. To visually see the difference, try temporarily setting the background property of the label elements that are giving you problems, and you'll see the element doesn't extend all the way to the textbox.

Radio Button Binding MVVM Application

I have a radiobutton.xaml file that has 4 radio buttons and a button
I showed radio button on the mainwindow by this code
<ContentControl Content="{StaticResource RB}" Height="326" x:Name="select" />
Now I need to implement binding for the radio button
I can't bind the radio buttons and the button to a view model. need to open new windows on behalf of the selected radio button on click of the button.
having difficulty in making V-M for radio button. don't know exactly where to put the binding code ...
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:src="clr-namespace:DiagramDesigner">
<GroupBox x:Key="RB" Header="Select The Architecture Modeling Style" Height="400" >
<StackPanel>
<TextBlock Text="Custom Style Architecture Modeling:" FontSize="20"
Margin="30 30 40 10" HorizontalAlignment="Center" />
<RadioButton Content="Custome Architecture Modeling" Margin="50 0 10 10"
GroupName="Standard" />
<TextBlock Text="Standard Style Architecture Modeling:" FontSize="20"
Margin="30 0 40 10" HorizontalAlignment="Center" />
<RadioButton Content="3-Tier Architecture Modeling" Margin="50 0 10 0"
GroupName="Standard" />
<RadioButton Content="Client-Server Architecture Modeling"
Margin="50 0 10 0" GroupName="Standard" />
<RadioButton Content="Pipeline and Filter Architecture Modeling"
Margin="50 0 10 0" GroupName="Standard" />
<Button Margin="100 20 100 0" Width="200" HorizontalContentAlignment="Center">
<Button.Content>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="4*"/>
<RowDefinition Height="1*"/>
</Grid.RowDefinitions>
<TextBlock Grid.Row="1" Text="Let's Go Draw It..." VerticalAlignment="Bottom" HorizontalAlignment="Center"/>
</Grid>
</Button.Content>
</Button>
</StackPanel>
</GroupBox>
</ResourceDictionary>
need to bind it as MVVM

I'd recommend you to use the ListBox method instead of the one you mentioned. You may find it here:
http://www.codeproject.com/Tips/807025/WPF-MVVM-Binding-for-Multiple-Radio-Buttons
If you'd like to keep the "abstract" groups (custom and standard style architecture modeling), then one of the solution that comes to my mind now is to implement a TextBox in the ControlTemplate and bind it to a property on the view model.
<ListBox ItemsSource="{Binding RadioCollection}" SelectedItem="{Binding SelectedRadio}">
<ListBox.ItemContainerStyle>
<Style TargetType="{x:Type ListBoxItem}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ListBoxItem}">
<TextBlock Text="{Binding AbstractGroupHeader}" />
<RadioButton
Content="{Binding Header}" ToolTip="{Binding ToolTip}"
IsChecked="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=IsSelected}"/>
</ControlTemplate>
</Setter.Value>
</Setter>
<Setter Property="Margin" Value="5"/>
</Style>
</ListBox.ItemContainerStyle>
</ListBox>
The view model basically is responsible for the view's state (e.g. an animation on the view isn't definied in the view model, but the view model may release, as in start it). VM is a class that you define and it must implement INotifyPropertyChanged interface found in namespace System.ComponentModel in case you want the view to be notified when you change property's value in code. Keep in mind, that the property must have a public access modifier, in order for the binding to work. If you want to follow this method, then read the article located under the link I gave. However, if you want a simpler solution, which will work with your code, then you have to bind IsChecked dependency property of each of the radio buttons to appropriate properties on the view model, like this:
<RadioButton Content="Pipeline and Filter Architecture Modeling"
Margin="50 0 10 0" GroupName="Standard" IsChecked="{Binding IsPipelinedModeling}"/>
And the VM in this case would look like this:
public class SettingsViewModel : INotifyPropertyChanged
{
bool _isPipelinedModeling;
public bool IsPipelinedModeling
{
get { return _isPipelinedModeling; }
set
{
if (_isPipelinedModeling == value)
return;
_isPipelinedModeling = value;
RaisePropertyChanged();
}
}
#region INotifyPropertyChanged implementation
public void RaisePropertyChanged([CallerMemberName]string propertyName = "")
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
public event PropertyChangedEventHandler PropertyChanged;
#endregion INotifyPropertyChanged implementation
}
To bind the view model to the view you can use either "view first" or "view model first" approach. I'm using view first. In the constructor of the window, user control or whatever you're using, add the following code:
this.Loaded += (s, e) =>
{
this.DataContext = new SettingsViewModel();
};
The code creates a new view model object and sets it as the window's DataContext.
Binding to a button is a little bit different though, because you have to declare a command. It is a class of your own, implementing ICommand interface:
ICommand _drawModelingArchitectureCommand;
public ICommand DrawModelingArchitectureCommand
{
get
{
return _drawModelingArchitectureCommand ?? (_drawModelingArchitectureCommand = new DrawTheModelingArchitectureCommand());
}
}
public class DrawTheModelingArchitectureCommand : ICommand
{
public bool CanExecute(object parameter)
{
// the code that decides whether the button will be enabled or not
return true;
}
public event EventHandler CanExecuteChanged;
public void Execute(object parameter)
{
// the code that is executed when the button is pressed
}
}
And finally the XAML for the button:
<Button Grid.Row="1" Content="Let's Go Draw It..." VerticalAlignment="Bottom" HorizontalAlignment="Center" Command="{Binding DrawTheModelingArchitecture}"/>

Putting a ContentControl *inside* a WPF DataTemplate?

I have a custom Expander control called SpecialExpander. It is basically just a standard Expander with a fancy header and a couple properties (HeaderText and IsMarkedRead).
I began by creating a simple class:
public class SpecialExpander : Expander
{
public string HeaderText { get; set; }
public bool IsMarkedRead { get; set; }
}
Then I created a style that sets a couple properties on the expander (e.g., margins, padding, etc.) and, importantly, it also defines a custom DataTemplate for the HeaderTemplate property. The template is basically a grid with two rows.
As shown in the illustrations below...
for the top row, I'd like a fixed layout (it's always TextBlock TextBlock CheckBox)
for the bottom row, however, I want to be able to provide custom XAML for each expander.
I tried putting <ContentControl Grid.Row="1" ... /> in the DataTemplate, but I couldn't figure out how to hook it up properly.
alt text http://img85.imageshack.us/img85/1194/contentcontrolwithintem.jpg
Question
How can I build a DataTemplate for my SpecialExpander so that the header has some fixed content (top row) and a place-holder for custom content (bottom row)?
For the second illustration, I would want to be able to do something like this:
<SpecialExpander HeaderText="<Expander Header Text>" IsMarkedRead="True">
<SpecialExpander.Header>
<StackPanel Orientation="Horizontal">
<RadioButton Content="High" />
<RadioButton Content="Med" />
<RadioButton Content="Low" />
</StackPanel>
<SpecialExpander.Header>
<Grid>
<Label>Main Content Goes Here</Label>
</Grid>
</SpecialExpander>

It hit me this morning how to solve this: instead of building a SpecialExpander, I just need a normal Expander. Then, for the header, I will use a custom ContentControl called SpecialExpanderHeader.
Here's how it works...
SpecialExpanderHeader class:
public class SpecialExpanderHeader : ContentControl
{
public string HeaderText { get; set; }
public bool IsMarkedRead { get; set; }
}
SpecialExpanderHeader style:
<Style TargetType="custom:SpecialExpanderHeader">
<Setter Property="Padding" Value="10" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="custom:SpecialExpanderHeader">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="5" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<StackPanel Grid.Row="0" Orientation="Horizontal">
<TextBlock Text="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=custom:SpecialExpanderHeader}, Path=HeaderText}" />
<CheckBox Margin="100,0,0,0" IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType=custom:SpecialExpanderHeader}, Path=IsMarkedRead}" />
</StackPanel>
<Separator Grid.Row="1" />
<ContentPresenter Grid.Row="2" />
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
Expander style
<Style x:Key="Local_ExpanderStyle" TargetType="Expander" BasedOn="{StaticResource {x:Type Expander}}">
<Setter Property="Margin" Value="0,0,0,10" />
<Setter Property="Padding" Value="10" />
<Setter Property="FontSize" Value="12" />
</Style>
Usage
<Expander Style="{StaticResource Local_ExpanderStyle}">
<Expander.Header>
<custom:SpecialExpanderHeader IsMarkedRead="True" HeaderText="Test">
<StackPanel Orientation="Horizontal">
<RadioButton Content="High" />
<RadioButton Content="Medium" />
<RadioButton Content="Low" />
</StackPanel>
</custom:SpecialExpanderHeader>
</Expander.Header>
<Grid>
<!-- main expander content goes here -->
</Grid>
</Expander>