问命令绑定在上下文相关菜单上不起作用？

EN

<UserControl Name="PFDBUserCtrl" x:Class="BFSimMaster.BFSMTreeview"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:local="clr-namespace:BFSimMaster.ViewModel"
         xmlns:cmd="clr-namespace:BFSimMaster.Commands"
         mc:Ignorable="d" 
         d:DesignHeight="66" d:DesignWidth="300">
<UserControl.Resources>
    <!--cmd:ActivateProjectCmd x:Key="CMDActivateProject"/-->
    <!--cmd:DeActivateProjectCmd x:Key="CMDDeActivateProject"/-->
</UserControl.Resources>
<DockPanel>
    <!-- PF Object Browser TREE -->
    <TreeView Name="PFDataBrowser" ItemsSource="{Binding LevelOnePFObjects}" >  
        <TreeView.Resources>
            <ContextMenu x:Key ="ProjectMenu"  StaysOpen="true" >
                <!-- Text="{Binding Source={StaticResource myDataSource}, Path=PersonName}-->
                <!--MenuItem Header="Activate" Command="{Binding Source={StaticResource CMDActivateProject}}" CommandParameter="{Binding Path=PlacementTarget,RelativeSource={RelativeSource AncestorType=ContextMenu}}"/-->
                <MenuItem Header="Activate" Command="{Binding DataContext.CMDActivateProject, RelativeSource={RelativeSource AncestorType={x:Type UserControl}}}" CommandParameter="{Binding Path=PlacementTarget,RelativeSource={RelativeSource AncestorType=ContextMenu}}"/>
                <MenuItem Header="Deactivate" Command="{Binding Source=TVViewModel, Path=CMDDeActivateProject}" CommandParameter="{Binding Path=PlacementTarget,RelativeSource={RelativeSource AncestorType=ContextMenu}}"/>
            </ContextMenu>
        </TreeView.Resources>
        <TreeView.ItemContainerStyle>
            <!-- This Style binds a TreeViewItem to a PFObject View Model.-->                
            <Style TargetType="{x:Type TreeViewItem}">                    
                <EventSetter Event="MouseRightButtonDown" Handler="OnRightButtonDown"/>
                <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}" />
                <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
                <Setter Property="FontWeight" Value="Normal" />

                <Style.Triggers>
                    <Trigger Property="IsSelected" Value="True">
                        <Setter Property="FontWeight" Value="Bold" />
                    </Trigger>                        
                </Style.Triggers>

            </Style>
        </TreeView.ItemContainerStyle>

        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                <TextBlock Text="{Binding Name}" />
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>
</DockPanel>

using System;
namespace BFSimMaster
{

public partial class BFSMTreeview : UserControl
{

    readonly TreeViewItemViewModel mViewModelPFObjBrowserTree;  
    public BFSMTreeview()
    {
        InitializeComponent();

        WApplication appPF = PFAPIUtils.APIInstance.GetApplication();
        WDataObject User = appPF.GetCurrentUser();



        // Get raw objects - tree data from a PF database.
        //BFPFDataObject userdb = new BFPFDataObject(User,false,"*.IntPrj");
        BFPFDataObject userdb = new BFPFDataObject(User, true);

        // Create UI-friendly wrappers around the 
        // raw data objects (i.e. the view-model).
        mViewModelPFObjBrowserTree = new TreeViewItemViewModel(userdb);

        // Let the UI bind to the view-model.
        base.DataContext = mViewModelPFObjBrowserTree;

    }
    public TreeViewItemViewModel TVViewModel
    {
        get { return mViewModelPFObjBrowserTree; }
    }

    private void OnRightButtonDown(object sender, MouseButtonEventArgs e)
    {
        //MessageBox.Show("Right Clicked on tree view");
        if (sender is TreeViewItem)
        {
            e.Handled = true;
            (sender as TreeViewItem).IsSelected = true;

            string strObjectType = ((sender as TreeViewItem).Header as PFObjectViewModel).PFDataObject.mThisPFObject.GetClassName().GetString();
            switch (strObjectType)
            {
                case "IntPrj":
                    (sender as TreeViewItem).ContextMenu = PFDataBrowser.Resources["ProjectMenu"] as System.Windows.Controls.ContextMenu;
                    (sender as TreeViewItem).ContextMenu.PlacementTarget = (sender as TreeViewItem); 
                    break;
                case "Folder":
                    (sender as TreeViewItem).ContextMenu = PFDataBrowser.Resources["ProjectMenu"] as System.Windows.Controls.ContextMenu;
                    break;
            }

        }
    }
}

using System;
namespace BFSimMaster.ViewModel
{

public class TreeViewItemViewModel 
{
    #region Data

    readonly ReadOnlyCollection<PFObjectViewModel> mLevelOnePFObjects;
    readonly PFObjectViewModel mRootOfPFObjects;

    #endregion // Data

    #region Constructor


    public TreeViewItemViewModel(BFPFDataObject rootOfPFObjectsA)
    {
        this.CMDActivateProject = new ActivateProjectCmd();
        this.CMDDeActivateProject = new DeActivateProjectCmd();
        mRootOfPFObjects = new PFObjectViewModel(rootOfPFObjectsA);

        mLevelOnePFObjects = new ReadOnlyCollection<PFObjectViewModel>(
            new PFObjectViewModel[] 
            { 
                mRootOfPFObjects 
            });            
    }

    #endregion // Constructor
    public ICommand CMDActivateProject { get; set; }
    public ICommand CMDDeActivateProject { get; set; }

    public ReadOnlyCollection<PFObjectViewModel> LevelOnePFObjects
    {
        get { return mLevelOnePFObjects; }
    }       

}
}