Develop Reference

How can I bind my list Property of the object to combo box submenus?

I have this object of class type HouseInfo that contains a list property:
public class HouseInfo
{
public string House
{
get;
set;
}
public List<String> Details
{
get;
set;
}
}
public List<HouseInfo> HouseInfos { get; set; }
I am successfully binding the House property to main items of combo box using ItemSource property in xaml but can't figure out the binding of Details to their respective submenus.
<ComboBox x:Name="Houses1"
Grid.Row="1"
Grid.Column="4"
ItemsSource="{Binding HouseInfos}"
Padding="0"
DisplayMemberPath="House"
VerticalContentAlignment="Center"
VerticalAlignment="Top"
HorizontalContentAlignment="Stretch"
Margin="0,0,0,2">
</ComboBox>
I tried customizing menuitems in xaml but I get the error "itemsCollection must be empty before using items Source."
How do I get the Details list in each menu item as submenu items?
Any help would be appreciated. Thanks in advance.
Update:
I have bound submenu items as well but they are not visible. I am sure they have bound successfully as it generates submenu items equal to the count of the list inside the details property list of the object. This is the updated xaml for the menu:
<Menu x:Name="menu"
VerticalAlignment="Top"
Grid.Row="1"
Grid.Column="4"
Height="19">
<MenuItem ItemsSource="{Binding HouseInfos}"
Padding="0"
Background="#0068FF11"
VerticalAlignment="Top"
RenderTransformOrigin="0.5,0.5"
Height="19"
Width="105">
<MenuItem.RenderTransform>
<TransformGroup>
<ScaleTransform />
<SkewTransform />
<RotateTransform />
<TranslateTransform X="0.5" />
</TransformGroup>
</MenuItem.RenderTransform>
<MenuItem.Header>
<Label x:Name="headerYears"
Margin="0"
Padding="0"
Content="Houses"
Background="#00FF0000"
MaxHeight="18"
UseLayoutRounding="False"
RenderTransformOrigin="0,0"
HorizontalContentAlignment="Center" />
</MenuItem.Header>
<MenuItem.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Header"
Value="{Binding House}" />
<Setter Property="ItemsSource"
Value="{Binding InfoPoints}" />
</Style>
</MenuItem.ItemContainerStyle>
</MenuItem>
</Menu>
Here is the image of menu which is populated but not visible.
Bound but invisible submenu items

Try using the DataSource property of the combobox. You can assign HouseInfos.House1.
What I did was I dynamically assign them to the combobox
comboBox1.DataSource = HouseInfo.House1.Details;
comboBox1.DisplayMember = "HouseDetails";
comboBox1.ValueMember = "HouseDetailsID";
Or you can try something like the above.

Use this structure. I matched the names with your own names.
MainWindw.xaml
<Window x:Class="MyNameSpace.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MyNameSpace"
mc:Ignorable="d"
Title="TestMenu" Height="450" Width="800">
<DockPanel>
<Menu DockPanel.Dock="Top" ItemsSource="{Binding MenuItems}">
<Menu.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Command" Value="{Binding Command}" />
</Style>
</Menu.ItemContainerStyle>
<Menu.ItemTemplate>
<HierarchicalDataTemplate DataType="{x:Type local:HouseInfo}" ItemsSource="{Binding Path=Details}">
<TextBlock Text="{Binding House}"/>
</HierarchicalDataTemplate>
</Menu.ItemTemplate>
</Menu>
<Grid>
</Grid>
</DockPanel>
</Window>
MainWindow.cs
using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Input;
namespace MyNameSpace
{
/// <summary>
/// Interaction logic for MainWindw.xaml
/// </summary>
public partial class MainWindw : Window
{
public List<HouseInfo> MenuItems { get; set; }
public MainWindw()
{
InitializeComponent();
MenuItems = new List<HouseInfo>();
HouseInfo houseInfo1 = new HouseInfo();
houseInfo1.House = "Header A";
houseInfo1.Details = new List<HouseInfo>() { new HouseInfo() { House = "Header A1" }, new HouseInfo() { House = "Header A2" } };
HouseInfo houseInfo2 = new HouseInfo();
houseInfo2.House = "Header B";
houseInfo2.Details = new List<HouseInfo>() { new HouseInfo() { House = "Header B1" }, new HouseInfo() { House = "Header B2" } };
MenuItems.Add(houseInfo1);
MenuItems.Add(houseInfo2);
DataContext = this;
}
}
public class HouseInfo
{
public string House
{
get;
set;
}
public List<HouseInfo> Details { get; set; }
private readonly ICommand _command;
public HouseInfo()
{
_command = new CommandViewModel(Execute);
}
public ICommand Command
{
get
{
return _command;
}
}
private void Execute()
{
// (NOTE: In a view model, you normally should not use MessageBox.Show()).
MessageBox.Show("Clicked at " + House);
}
}
public class CommandViewModel : ICommand
{
private readonly Action _action;
public CommandViewModel(Action action)
{
_action = action;
}
public void Execute(object o)
{
_action();
}
public bool CanExecute(object o)
{
return true;
}
public event EventHandler CanExecuteChanged
{
add { }
remove { }
}
}
}
you can gave style to every element with this code
<Menu.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Command" Value="{Binding Command}" />
</Style>
</Menu.ItemContainerStyle>
for example add this line to HouseInfo class
public Thickness Margin { get; set; }
and MainWindow.cs
MenuItems = new List<HouseInfo>();
HouseInfo houseInfo1 = new HouseInfo();
houseInfo1.House = "Header A";
houseInfo1.Margin = new Thickness(5);
houseInfo1.Details = new List<HouseInfo>() { new HouseInfo() { House = "Header A1" }, new HouseInfo() { House = "Header A2", Margin=new Thickness(10) } };
and set Style in xaml
<Menu.ItemContainerStyle>
<Style TargetType="{x:Type MenuItem}">
<Setter Property="Command" Value="{Binding Command}" />
<Setter Property="Margin" Value="{Binding Margin}" />
</Style>
</Menu.ItemContainerStyle>
test:

WPF - Changes in treeviewitems' properties not reflected in UI problem

I have a tree view built with HierarchicalDataTemplates, I want to be able to add JSON files to SegmentInfo nodes - if I do so, the data is added but the change is not reflected in UI (still the comment says "no data" in red).
I've made the list the tree view items as ObservableCollection, moved it to a "ViewModel" class that inherits INotifyPropertyChanged, I seem to set it up properly, I've set DataContext to the ViewModel object in my Window.
In xaml I've set the bindings and mode as TwoWay. Still nothing helped
XAML:
<Window.Resources>
<local:BoolToStringConverter x:Key="BoolToStringConverter" FalseValue="no data" TrueValue="has data" />
</Window.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto" MinHeight="384.8"/>
<RowDefinition Height="35.2"/>
</Grid.RowDefinitions>
<TreeView Name="trvTypeInfos" Margin="5" Grid.Row="0" ItemsSource="{Binding Path=TypeInfoList, Mode=TwoWay}">
<TreeView.Resources>
<Style TargetType="{x:Type TreeViewItem}">
<EventSetter Event="ListBoxItem.PreviewMouseUp"
Handler="ListBoxItem_PreviewMouseUp"/>
<Setter Property="IsExpanded" Value="True"/>
</Style>
<HierarchicalDataTemplate DataType="{x:Type data:TypeInfo}" ItemsSource="{Binding SegmentInfos, Mode=TwoWay}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Name}" />
<TextBlock Text=" [" Foreground="Blue" />
<TextBlock Text="{Binding SegmentInfos.Count}" Foreground="Blue"/>
<TextBlock Text="]" Foreground="Blue" />
</StackPanel>
</HierarchicalDataTemplate>
<DataTemplate DataType="{x:Type data:SegmentInfo}">
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Name}" />
<TextBlock Text=" ("/>
<TextBlock Text="{Binding Path=HasData, Mode=TwoWay, Converter={StaticResource BoolToStringConverter}}">
<TextBlock.Style>
<Style TargetType="TextBlock">
<Style.Triggers>
<Trigger Property="Text" Value="no data">
<Setter Property="Foreground" Value="Red"/>
</Trigger>
<Trigger Property="Text" Value="has data">
<Setter Property="Foreground" Value="Green"/>
</Trigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
<TextBlock Text=")"/>
</StackPanel>
</DataTemplate>
</TreeView.Resources>
</TreeView>
<StackPanel Grid.Row="1" Orientation="Horizontal" HorizontalAlignment="Right">
<Button Width="80" Height="20" Content="OK" Margin="5,0, 5, 5" IsDefault="True" Click="OK_Click"/>
<Button Width="80" Height="20" Content="Cancel" Margin="5,0, 5, 5" Click="Cancel_Click" />
</StackPanel>
</Grid>
Window class:
public SegmentDataUpdaterDialog(SegmentDataUpdater segmentDataUpdater, List<TypeInfo> typeInfoList)
{
ViewModel = new ViewModel(typeInfoList);
DataContext = ViewModel;
SegmentDataUpdater = segmentDataUpdater;
InitializeComponent();
}
private void ListBoxItem_PreviewMouseUp(object sender, MouseButtonEventArgs e)
{
TreeViewItem item = sender as TreeViewItem;
SegmentInfo segInfo = item.Header as SegmentInfo;
if (segInfo != null)
{
MessageBox.Show(segInfo.JsonContents);
var filePath = AskForFile();
bool success = SegmentDataUpdater.TryStoreJson(segInfo, filePath, out string json);
if (success)
{
segInfo.JsonContents = json;
segInfo.HasData = true;
}
}
}
ViewModel class:
public class ViewModel : INotifyPropertyChanged
{
private ObservableCollection<TypeInfo> _typeInfoList;
public ObservableCollection<TypeInfo> TypeInfoList
{
get { return _typeInfoList; }
set
{
if (_typeInfoList==null || !value.All(_typeInfoList.Contains))
{
_typeInfoList = value;
OnPropertyChanged(nameof(TypeInfoList));
}
}
}
public event PropertyChangedEventHandler PropertyChanged;
public ViewModel(List<TypeInfo> typeInfos)
{
TypeInfoList = new ObservableCollection<TypeInfo>(typeInfos);
}
private void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
TypeInfo class:
public class TypeInfo
{
public string Name { get; set; }
public ObservableCollection<SegmentInfo> SegmentInfos { get; set; }
public int ElementId { get; set; }
public TypeInfo()
{
SegmentInfos = new ObservableCollection<SegmentInfo>();
}
}
SegmentInfo class:
public class SegmentInfo
{
public string Name { get; set; }
public bool HasData { get; set; }
public string JsonContents { get; set; }
public int ElementId { get; set; }
}
Converter classes:
public class BoolToValueConverter<T> : IValueConverter
{
public T FalseValue { get; set; }
public T TrueValue { get; set; }
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
if (value == null)
return FalseValue;
else
return (bool)value ? TrueValue : FalseValue;
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
return value != null ? value.Equals(TrueValue) : false;
}
}
public class BoolToStringConverter : BoolToValueConverter<String> { }
I expect that after successful adding json file to the SegmentInfo the UI will update the node with "has data" comment.
Now I can check that the data is really added to the SegmentInfo but UI doesn't reflect that.

Your HasData property does not update the UI, as you have no mechanism to update it (INotifyPropertyChanged). SegmentInfo needs to implement INotifyPropertyChanged.
If you plan to have a property Bind to the UI, it needs to have an PropertyChanged Notification go out for it individually. So on your SegmentInfo class; Name, HasData, and JsonContent should each raise an OnPropertyChanged event in their setter.
A good way to think of it; anything that is directly bound in XAML (Text="{Binding Name}") should raise an event when changed. If you bind any properties like: (Text="{Binding MyThing.Name}") you will not get an update when MyThing.Name changes. You need to break out the property and Notify on it directly.

Remove ListBoxItem on button click through ICommands

I just started with XAML/WPF and there are lots of questions going on in my head. One of them is how do we bind a button click to remove a ListBoxItem through the ICommand interface. I created a simple WPF project and here's my XAML:
<ListBox Name="lb" HorizontalAlignment="Left" Height="129" Margin="15,17,0,0" VerticalAlignment="Top" Width="314" Grid.ColumnSpan="2" >
<ListBox.Resources>
<Style TargetType="ListBoxItem">
<Setter Property="Height" Value="30" />
<Setter Property="OverridesDefaultStyle" Value="true" />
<Setter Property="SnapsToDevicePixels" Value="true" />
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="ListBoxItem">
<StackPanel Orientation="Horizontal">
<CheckBox Margin="5,5" Height="18" IsChecked="{TemplateBinding IsSelected}">
<ContentPresenter Content="{TemplateBinding Content}"/>
</CheckBox>
<Button Content="[x]" Height="22" Width="22" HorizontalAlignment="Right"
Command="{Binding ElementName=lb, Path=DataContext.DeleteItemCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ListBox}}}" CommandParameter="{Binding }"/>
</StackPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ListBox.Resources>
<ListBoxItem Content="Foo" />
<ListBoxItem Content="Bar" />
</ListBox>
And here's my Window:
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
DataContext = new Context(); // Also tried before InitializeComponent()
}
public class Context
{
public ICommand DeleteItemCommand = new DeleteItemCommand();
}
}
Where DeleteItemCommand is:
public class DeleteItemCommand : ICommand
{
public event EventHandler CanExecuteChanged;
public bool CanExecute(object parameter)
{
return true;
}
public void Execute(object parameter)
{
MessageBox.Show("Meep");
}
}
The questions are:
Why isn't the message box showing? How do I make it work?
How do I retrieve which index/ListBoxItem triggered the button
click?
How do I align the button to the end of the line?
Thanks a lot!

One problem you have there is your ICommand is just a variable.
You need a public property in order to bind.
More like
public ICommand DeleteItemCommand {get;set;} = new DeleteItemCommand();
Another problem is your elementname. This is subject to namescope and I think you'll find the listbox is in another namescope.
Instead, just use relativesource binding with ancestortype ListBox.
Roughly.
Command="{Binding DataContext.DeleteItemCommand,
RelativeSource={RelativeSource AncestorType={x:Type ListBox}}}
As an aside.
I recommend looking into a framework to make commands and suchlike easier.
MVVMLight would be my suggestion. Add to a project using nuget mvvmlightlibs. https://msdn.microsoft.com/en-gb/magazine/dn237302.aspx?f=255&MSPPError=-2147217396
The following is based on some code I already had so it's illustrative rather than exactly what you're doing.
View:
<Window.DataContext>
<local:MainWindowViewModel/>
</Window.DataContext>
<Grid>
<ListBox ItemsSource="{Binding People}"
HorizontalContentAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="100"/>
</Grid.ColumnDefinitions>
<TextBlock Text="{Binding LastName}"/>
<Button Content="Delete"
Command="{Binding DataContext.DeletePersonCommand, RelativeSource={RelativeSource AncestorType=ListBox}}"
CommandParameter="{Binding}"
Grid.Column="1"/>
</Grid>
</DataTemplate>
</ListBox.ItemTemplate>
</ListBox>
</Grid>
Viewmodel uses relaycommand from mvvmlight
using GalaSoft.MvvmLight.CommandWpf;
using System.Collections.ObjectModel;
namespace wpf_99
{
public class MainWindowViewModel : BaseViewModel
{
private RelayCommand<Person> deletePersonCommand;
public RelayCommand<Person> DeletePersonCommand
{
get
{
return deletePersonCommand
?? (deletePersonCommand = new RelayCommand<Person>(
(person) =>
{
People.Remove(person);
}
));
}
}
private ObservableCollection<Person> people = new ObservableCollection<Person>();
public ObservableCollection<Person> People
{
get { return people; }
set { people = value; }
}
public MainWindowViewModel()
{
People.Add(new Person { FirstName = "Chesney", LastName = "Brown" });
People.Add(new Person { FirstName = "Gary", LastName = "Windass" });
People.Add(new Person { FirstName = "Liz", LastName = "McDonald" });
People.Add(new Person { FirstName = "Carla", LastName = "Connor" });
}
}
}
BaseViewModel is pretty much as the msdn article on inotifypropertychanged shows:
public class BaseViewModel : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
protected void RaisePropertyChanged([CallerMemberName] String propertyName = "")
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
}
Mvvmlight has its own base viewmodel but you can't serialise a vm inherits from that.
Person:
public class Person : BaseViewModel
{
private string firstName;
public string FirstName
{
get { return firstName; }
set { firstName = value; RaisePropertyChanged(); }
}
private string lastName;
public string LastName
{
get { return lastName; }
set { lastName = value; RaisePropertyChanged(); }
}

How to bind to event in parent viewmodel from child viewmodel

I am currently following this guide for setting up a TreeView with checkboxes. In my code, the tree "FooViewModel" is initiated in my MainViewModel and bound to the TreeView as an ItemsSource. I want to be able to subscribe to some event in the MainViewModel that will trigger when something is checked or unchecked. That way I can iterate through the "FooViewModel" and check which nodes have IsChecked = True. How do I create this event binding?
This is the code I have:
<Style x:Key="TreeViewItemStyle" TargetType="TreeViewItem">
<Setter Property="IsExpanded" Value="False" />
<Setter Property="IsSelected" Value="{Binding IsInitiallySelected, Mode=OneTime}" />
<Setter Property="KeyboardNavigation.AcceptsReturn" Value="True" />
<Setter Property="xn:VirtualToggleButton.IsVirtualToggleButton" Value="True" />
<Setter Property="xn:VirtualToggleButton.IsChecked" Value="{Binding IsChecked}" />
<Setter Property="Focusable" Value="False" />
</Style>
<xn:TreeView ItemsSource="{Binding CollectionFooViewModel}" ItemContainerStyle="{StaticResource TreeViewItemStyle}">
<xn:TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children, Mode=OneTime}">
<StackPanel Orientation="Horizontal">
<CheckBox Focusable="False" IsChecked="{Binding IsChecked}" VerticalAlignment="Center"/>
<ContentPresenter Content="{Binding Name, Mode=OneTime}" Margin="2,0"/>
</StackPanel>
</HierarchicalDataTemplate>
</xn:TreeView.ItemTemplate>
</xn:TreeView>
I figured if there's a way to bind "IsChecked" to two properties (one in FooViewModel, another in MainViewModel) I would have my answer.

Lots of ways to achieve this. One would be some kind of a pub/sub (messaging) implementation or maybe just bunch of Action delegates? Something like...
MainWindow
<Window x:Class="WpfApplication1.View.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow"
Height="300"
Width="250">
<TreeView ItemsSource="{Binding CollectionFooViewModel}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Children, Mode=OneTime}">
<StackPanel Orientation="Horizontal">
<CheckBox Focusable="False"
IsChecked="{Binding IsChecked}"
VerticalAlignment="Center"/>
<ContentPresenter Content="{Binding Name, Mode=OneTime}"
Margin="2,0"/>
</StackPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
</Window>
DataContext
public class MainViewModel : ViewModelBase
{
public MainViewModel()
{
Action<MyItem> action = item => Console.WriteLine(#"MyItem was clicked");
CollectionFooViewModel = new ObservableCollection<MyItem>()
{
new MyItem()
{
Name = "MyItem1",
Children = new List<MyItem>()
{
new MyItem()
{
Name = "MySubItem1",
IsChecked = false,
Action = item => Console.WriteLine(#"{0} invoked action", item.Name)
},
new MyItem()
{
Name = "MySubItem2",
IsChecked = true,
Action = item => Console.WriteLine(#"{0} state is {1} ", item.Name, item.IsChecked)
},
},
Action = action
}
};
}
public ObservableCollection<MyItem> CollectionFooViewModel { get; set; }
}
public class MyItem : ViewModelBase
{
private bool _isChecked;
public string Name { get; set; }
public bool IsChecked
{
get { return _isChecked; }
set
{
_isChecked = value;
if (Action != null)
Action.BeginInvoke(this, null, null);
}
}
public IEnumerable<MyItem> Children { get; set; }
public Action<MyItem> Action { get; set; }
}
Which gives you the following...
...and spits this out to console when clicked in order.
MyItem was clicked
MySubItem1 invoked action
MySubItem2 state is False
Of course, in your case, you might want to pass concrete method to delegate.

Try adding "OnPropertyEventChanged" method call in the setter for your model, here is an example of what I mean:
https://msdn.microsoft.com/en-us/library/ms743695%28v=vs.110%29.aspx

Keybinding on a treeview item, with CommandParameter

I'm trying to execute a command located on my ViewModel, using a TreeViewItem with a KeyBinding, and a MenuContext.
Currently, using the context menu, the command is invoked on the correct ViewModel instance.
However, when I select a TreeViewItem and press the "C" key, the command is invoked on the "root" ViewModel.
I tried extending KeyBinding class as well ( Keybinding a RelayCommand ) with no luck.
Maybe I'm going to the wrong path : I just want to display the correct MessageBox, if I use the context menu or the key.
Code sample for a WPF project named WpfTest.
MainWindow.xaml
<Window x:Class="WpfTest.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:vm="clr-namespace:WpfTest"
Title="MainWindow" Height="350" Width="525">
<Grid>
<TreeView ItemsSource="{Binding}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Child}" DataType="{x:Type vm:ViewModel}">
<TextBlock Text="{Binding Name}" />
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<Setter Property="ContextMenu">
<Setter.Value>
<ContextMenu>
<MenuItem Header="{Binding Name}" Command="{Binding SomeCommand}" CommandParameter="{Binding}"/>
</ContextMenu>
</Setter.Value>
</Setter>
<Setter Property="vm:MyAttached.InputBindings">
<Setter.Value>
<InputBindingCollection>
<KeyBinding Key="C" Command="{Binding SomeCommand}" CommandParameter="{Binding}"/>
</InputBindingCollection>
</Setter.Value>
</Setter>
</Style>
</TreeView.ItemContainerStyle>
</TreeView>
</Grid>
</Window>
MainWindow.xaml.cs:
namespace WpfTest
{
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Windows;
using System.Windows.Input;
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
this.DataContext = new List<ViewModel>
{
new ViewModel
{
Name = "Parent",
Child = new ObservableCollection<ViewModel>
{
new ViewModel { Name = "Child 1" },
new ViewModel { Name = "Child 2" },
new ViewModel { Name = "Child 3" }
}
}
};
}
}
public class ViewModel
{
public string Name { get; set; }
public ObservableCollection<ViewModel> Child { get; set; }
public ICommand SomeCommand { get; set; }
public ViewModel()
{
this.SomeCommand = new RelayCommand<ViewModel>(OnCommandExecuted);
}
private void OnCommandExecuted(ViewModel parameter)
{
MessageBox.Show("CommandExecuted on " + Name + " with parameter " + parameter.Name);
}
}
public class MyAttached
{
public static readonly DependencyProperty InputBindingsProperty =
DependencyProperty.RegisterAttached("InputBindings", typeof(InputBindingCollection), typeof(MyAttached),
new FrameworkPropertyMetadata(new InputBindingCollection(),
(sender, e) =>
{
var element = sender as UIElement;
if (element == null) return;
element.InputBindings.Clear();
element.InputBindings.AddRange((InputBindingCollection)e.NewValue);
}));
public static InputBindingCollection GetInputBindings(UIElement element)
{
return (InputBindingCollection)element.GetValue(InputBindingsProperty);
}
public static void SetInputBindings(UIElement element, InputBindingCollection inputBindings)
{
element.SetValue(InputBindingsProperty, inputBindings);
}
}
public class RelayCommand<T> : ICommand
{
readonly Action<T> _execute = null;
public RelayCommand(Action<T> execute) { _execute = execute; }
public bool CanExecute(object parameter) { return true; }
public void Execute(object parameter) { _execute((T)parameter); }
public event EventHandler CanExecuteChanged { add { CommandManager.RequerySuggested += value; } remove { CommandManager.RequerySuggested -= value; } }
}
}

Here is the problem: The Style only creates one InputBindingCollection for all ListViewItems, you have to be very careful with Setter.Values for that reason.
And here is the fix:
<TreeView ItemsSource="{Binding}">
<TreeView.Resources>
<!-- x:Shared="False" forces the new creation of that object whenever referenced -->
<InputBindingCollection x:Shared="False" x:Key="InputBindings">
<KeyBinding Key="C" Command="{Binding SomeCommand}" CommandParameter="{Binding}" />
</InputBindingCollection>
</TreeView.Resources>
<!-- ... -->
<TreeView.ItemContainerStyle>
<Style TargetType="{x:Type TreeViewItem}">
<!-- ... -->
<Setter Property="vm:MyAttached.InputBindings" Value="{StaticResource InputBindings}"/>
</Style>
</TreeView.ItemContainerStyle>
</TreeView>