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Caliburn.micro get treeview's selected item by contextmenu onclick

I have a task to use a contextmenu in treeview and pass selected treeview's item to ViewModel by clicking on contextmenu element.
Here is my xaml:
<Window.Resources>
<HierarchicalDataTemplate x:Key="Ufps"
<StackPanel Orientation="Horizontal">
<TextBlock Text="{Binding Id}" />
<TextBlock Margin="5 0 0 0" Text="{Binding Name}" />
</StackPanel>
</HierarchicalDataTemplate>
</Window.Resources>
........
........
<TreeView x:Name="TrvUfpsDictionary" Height="222" Canvas.Left="25"
Canvas.Top="280" Width="545"
Background="AliceBlue"
ItemsSource="{Binding Path=Ufps, Mode=OneWay}"
ItemTemplate="{StaticResource Ufps}">
<TreeView.ContextMenu>
<ContextMenu>
<MenuItem Header="Add Element"
cal:Message.Attach="[Event Click] = [Action AddElement(TrvUfpsDictionary.SelectedItem)]"
/>
................
</ContextMenu>
</TreeView.ContextMenu>
</TreeView>
........
<Button Content="Test" Canvas.Left="475" Canvas.Top="568" Width="75"
cal:Message.Attach="[Event Click] = [Action AddElement(TrvUfpsDictionary.SelectedItem)]"/>
And here is simple ViewModel's code:
public class UserSettingsViewModel : PropertyChangedBase
{
..........
public void AddElement(object selectedItem)
{
MessageBox.Show("Element added! "+selectedItem.?GetHashCode());
}
..........
}
Now I've stuck with it. When I've selected treeview's item and then I've pressed the "Test" button - it works fine, it pass the selected item to "AddElement" in my VM. BUT when I do the same with contextmenu - it always pass null. Did I miss something?
EDIT
I've made a simple app with the problem described. https://github.com/whizzzkey/WpfApp1

You might have to move the Context Menu further into the TreeView, into the Item Template and add Context Menu to the Label/TextBlock you have in nodes.
For example, consider the following Employee tree (emulating since I do not know your data structure),
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Positions}" >
<Label Content="{Binding DepartmentName}"/>
<HierarchicalDataTemplate.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Employees}" >
<Label Content="{Binding PositionName}"
Tag="{Binding DataContext, ElementName=TestControl}" >
<Label.ContextMenu>
<ContextMenu
cal:Action.TargetWithoutContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Add Element"
cal:Message.Attach="[Event Click] = [Action AddElement($datacontext)]"/>
</ContextMenu>
</Label.ContextMenu>
</Label>
<HierarchicalDataTemplate.ItemTemplate>
<DataTemplate>
<Label Content="{Binding EmployeeName}"
Tag="{Binding DataContext, ElementName=TestControl}">
<Label.ContextMenu>
<ContextMenu
cal:Action.TargetWithoutContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Add Element"
cal:Message.Attach="[Event Click] = [Action AddElement($datacontext)]" />
</ContextMenu>
</Label.ContextMenu>
</Label>
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
There are couple of important points to note here. Since your method exists in ViewModel and you have to ensure that the DataContext is pointing to your ViewModel instead of the Item Type that is bound to node.
For this, you need can make use of cal:Action.TargetWithoutContext. The following line the Label definition ensure we have access to the View's DataContext.
Tag="{Binding DataContext, ElementName=TestControl}"
While the following line ensures the we get our bindings right (to ViewModel). TestControl is the x:Name for your UserControl
cal:Action.TargetWithoutContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}"
Finally the Click Action would be modified as following.
cal:Message.Attach="[Event Click] = [Action AddElement($datacontext)]"
This would ensure your ViewModel's Action is called with the right parameter passed.
Update
Based on your comment and code,following are the changes required.
Window Definition : Add x:Name
<Window
x:Class="WpfApp1.Views.ShellView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:cal="http://www.caliburnproject.org"
Title="XmlData Tree Test"
x:Name="TestControl"
Width="250"
Height="350">
Root Hierarchical Template
Associating Item source with Tag is placed on the TextBlock, also the Relative Source has Self.
<HierarchicalDataTemplate DataType="root" ItemsSource="{Binding XPath=./*}" >
<StackPanel Orientation="Horizontal">
<TextBlock Margin="0" Text="ROOT"
Tag="{Binding DataContext, ElementName=TestControl}">
<TextBlock.ContextMenu>
<ContextMenu
cal:Action.TargetWithoutContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Add Element"
cal:Message.Attach="[Event Click] = [Action AddElement($datacontext)]" />
</ContextMenu>
</TextBlock.ContextMenu>
</TextBlock>
</StackPanel>
</HierarchicalDataTemplate>
Hierarchical Template for Node
<HierarchicalDataTemplate
DataType="Node"
ItemsSource="{Binding XPath=./*}">
<StackPanel Orientation="Horizontal">
<TextBlock Margin="0" Text="Node:" />
<TextBlock Margin="5,0,0,0"
Tag="{Binding DataContext, ElementName=TestControl}"
Text="{Binding XPath=#name}" >
<TextBlock.ContextMenu>
<ContextMenu
cal:Action.TargetWithoutContext="{Binding PlacementTarget.Tag, RelativeSource={RelativeSource Self}}">
<MenuItem Header="Add Element"
cal:Message.Attach="[Event Click] = [Action AddElement($datacontext)]" />
</ContextMenu>
</TextBlock.ContextMenu>
</TextBlock>
</StackPanel>
</HierarchicalDataTemplate>
Output Example,
For Root
For Node,

Dynamically binding and statically adding MenuItems - using view Models/MVVM

I'm trying to have a dynamic menu item using MVVM from an observable collection. Everything worked, but then I needed to add a "add new" button to the end. I found a solution using a CompositeCollection, like here:
How do I dynamically bind and statically add MenuItems?
So have the following code, where TimeSpans is a collection of ViewModels:
<MenuItem Header="Time Ranges">
<MenuItem.ItemsSource>
<CompositeCollection>
<CollectionContainer Collection="{Binding TimeSpans}" />
<Separator />
<MenuItem Header="Add New" cal:Message.Attach="NewTimeSpan()" />
</CompositeCollection>
</MenuItem.ItemsSource>
<MenuItem.ItemTemplate>
<ItemContainerTemplate>
<MenuItem Header="{Binding Name}" cal:Message.Attach="ConfigureTimeSpan()" />
</ItemContainerTemplate>
</MenuItem.ItemTemplate>
</MenuItem>
However, the view models are not populated like it was just using ItemsSource="{Binding TimeSpans}", it's not showing anything:
I suspect this is because I'm in the StackOverflow answer above the binding is actually a collection of MenuItems, so that composite collection makes sense. Whereas mine's mixing ViewModels & MenuItems.
Is there any way to construct the collection of menu-items created from ViewModels in the XAML so I can bind it?

For anyone else who comes across this, as Szabolcs Dezsi said, I needed to use a resource for the CollectionViewSource (bad reading comprehension on my part, as that was in the answer linked in my question).
Working code below:
<MenuItem Header="Time Ranges" x:Name="TimeRangesMenuItem">
<MenuItem.Resources>
<CollectionViewSource Source="{Binding ElementName=TimeRangesMenuItem, Path=TimeSpans}" x:Key="TimeSpanMenuItems" />
</MenuItem.Resources>
<MenuItem.ItemsSource>
<CompositeCollection>
<CollectionContainer Collection="{Binding Source={StaticResource TimeSpanMenuItems}}" />
<Separator />
<MenuItem Header="Add New" cal:Message.Attach="NewTimeSpan()" />
</CompositeCollection>
</MenuItem.ItemsSource>
<MenuItem.ItemTemplate>
<ItemContainerTemplate>
<MenuItem Header="{Binding Name}" cal:Message.Attach="ConfigureTimeSpan()" />
</ItemContainerTemplate>
</MenuItem.ItemTemplate>
</MenuItem>

WPF - Create Context Menu mixing static and dynamic items

I try to create Context Menu mixing static and dynamic items.
this is the code:
<CollectionViewSource x:Key="DynamicMenuBridge" Source="{Binding Path=MyMenuCollection}" />
<ContextMenu x:Key="_Menu" >
<ContextMenu.ItemsSource>
<CompositeCollection>
<MenuItem Header="A" Click="..."/>
<Separator/>
<CollectionContainer Collection="{Binding Source={StaticResource DynamicMenuBridge}}" >
</CollectionContainer>
<Separator/>
<MenuItem Header="b" Click ="..."/>
<MenuItem Header="c" Click="..."/>
</CompositeCollection>
</ContextMenu.ItemsSource>
</ContextMenu>
But it does not work, why ?
(in debuging by snoop. it looks like that the CollectionContainer does not exist)

WPF, TreeViewItem, how to not show contextMenu according to dependency property?

I have a treeview using the following style:
<HierarchicalDataTemplate x:Key="itemTemplate" DataType="{x:Type AttCatalog:AttachmentCatalogModel}" ItemsSource="{Binding Children}">
<TextBlock Text="{Binding Name}" Tag="{Binding Guid}">
<TextBlock.ContextMenu>
<ContextMenu>
<MenuItem Header="New Item"/>
<MenuItem Header="Move to..." />
<MenuItem Header="Delete" />
</ContextMenu>
</TextBlock.ContextMenu>
</TextBlock>
</HierarchicalDataTemplate>
<TreeView x:Name="tree" HorizontalAlignment="Left" Width="216" BorderThickness="0,0,1,0" Background="#FFFBFBFB" IsEnabled="{Binding IsEnabled}" ItemsSource="{Binding Catalogs}" ItemTemplate="{StaticResource itemTemplate}" TreeViewItem.Expanded="OnExpandItemHandler" Margin="0,0,0,241" SelectedItemChanged="tree_SelectedItemChanged">
you can see TextBlock Tag binding a Guid property, my question is, how to do that when this Guid is empty (00000-00000000-00000), not show the contextMenu?

In your context menu, bind the visibility to the Guid, and treat it with a converter =>
<ContextMenu Visibility="{Binding Element=Guid,
Converter={StaticResource GuidToVisibilityConverter}}">
<MenuItem Header="New Item"/>
<MenuItem Header="Move to..." />
<MenuItem Header="Delete" />
</ContextMenu>
In your converter, you can treat your Guid value the way you want, to either return Visibility.Visible or Visibility.Hidden, depending on the value.
You can find more information on converters here.
Hope that helped !

Hirearchial Data Template RadTreeView issue

I want to bind data to radtreeview through Hireachical Data Template. With Wpf treeview Its working. We wanted to change that to Radtreeview. When i am trying to achieve the same i am not getting that.
<TreeView Name="treeview2"
Grid.RowSpan="2" Tag=""
Grid.ColumnSpan="2"
ItemContainerStyle="{StaticResource StretchTreeViewItemStyle}" ItemsSource="{Binding Path=Cluster}" Width="250" Height="251" Margin="0,0,0,0" DockPanel.Dock="Bottom">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Nodes}">
<DockPanel LastChildFill="True">
<TextBlock Padding="15,0,30,0" Text="{Binding Path=numitems}" TextAlignment="Right" DockPanel.Dock="Right"/>
<TextBlock Text="{Binding Path=Text}" DockPanel.Dock="Left" TextAlignment="Left">
<TextBlock.ContextMenu>
<ContextMenu>
<MenuItem Header="Rename" />
<MenuItem Header="Exlcude"/>
</ContextMenu>
</TextBlock.ContextMenu>
</TextBlock>
</DockPanel>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
I am looking for a sample which shows that bind a property. Cluster is a observablecollection property of type a class. Nodes is a child collection with in that. I am looking for transforming the same code to radtreeview-- Thanks