Tree View Command not working on context menu

Question

I am working on a WPF application. It contains a multi select tree view. The tree is supposed to have different context menu items for each node(i.e at each level of the tree). I am able to populate the tree and even get the context menu to have different options based on the type of data in the tree view. Once i have done this, the command bindings to the context menu items has stopped working. i get an error in the output window as below:

System.Windows.Data Error: 40 : BindingExpression path error: 'RefreshEvent' property not found on 'object' ''RootNameList' (HashCode=49313939)'. BindingExpression:Path=RefreshEvent; DataItem='RootNameList' (HashCode=49313939); target element is 'MenuItem' (Name=''); target property is 'Command' (type 'ICommand')

As it is visible in the error, the DataItem is not pointing to the intended ViewModel. Can anyone help me to resolve this issue.

I have attached the code as an attachment.7588-treeview.xml

Answer 1

Hi, try following demo and accept the helpful as answer:

XAML:

<Window x:Class="Window012"
        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:WpfApp1.WpfApp012"
        mc:Ignorable="d"
        Title="Window012" Height="450" Width="800">
  <Window.Resources>
    <local:ViewModel x:Key="vm"/>
  </Window.Resources>
  <Grid DataContext="{StaticResource vm}">
    <TreeView ItemsSource="{Binding TreeViewDataCollection}">
      <TreeView.Resources>
        <ContextMenu x:Key="ChildMenu" >
          <MenuItem Header="Get Configuration" 
                    Command="{Binding GetConfigurationEvent, Source={StaticResource vm}}"
                    CommandParameter="{Binding}"/>
          <MenuItem Header="Put Configuration" 
                    Command="{Binding PutConfigurationEvent, Source={StaticResource vm}}"
                    CommandParameter="{Binding}"/>
        </ContextMenu>
      </TreeView.Resources>
      <TreeView.ItemContainerStyle>
        <Style TargetType="{x:Type TreeViewItem}">
          <Setter Property="ContextMenu" Value="{StaticResource ChildMenu}"/>
        </Style>
      </TreeView.ItemContainerStyle>
      <TreeView.ItemTemplate>
        <HierarchicalDataTemplate ItemsSource="{Binding HostGroupName}" DataType="{x:Type local:RootNameList}">
          <Label Content="{Binding RootSubnet}"/>
        </HierarchicalDataTemplate>
      </TreeView.ItemTemplate>
    </TreeView>
  </Grid>
</Window>

ViewModel:

Imports System.ComponentModel

Namespace WpfApp012

  Public Class ViewModel

    Public Sub New()
      For i = 1 To 10
        Dim rnl As New RootNameList With {.RootSubnet = $"RootSubnet{i}"}
        For k = 1 To 10
          rnl.HostGroupName.Add(New RootNameList With {.RootSubnet = $"HostGroupName {k + i * 10}"})
        Next
        col.Add(rnl)
      Next
      cvs.Source = col
    End Sub

    Private cvs As New CollectionViewSource
    Private col As New AsyncObservableCollection(Of RootNameList)
    Public ReadOnly Property TreeViewDataCollection As ICollectionView
      Get
        Return cvs.View
      End Get
    End Property
    Public ReadOnly Property GetConfigurationEvent As ICommand
      Get
        Return New RelayCommand(Sub(state)
                                  Debug.WriteLine($"Get: {CType(state, RootNameList).RootSubnet}")
                                End Sub)
      End Get
    End Property
    Public ReadOnly Property PutConfigurationEvent As ICommand
      Get
        Return New RelayCommand(Sub(state)
                                  Debug.WriteLine($"Put: {CType(state, RootNameList).RootSubnet}")
                                End Sub)
      End Get
    End Property

  End Class

  Public Class RootNameList
    Public Property RootSubnet As String
    Public Property HostGroupName As New List(Of RootNameList)
  End Class

End Namespace