Get Treeviewitem from Menu Context. WPF XAML MVVM

Question

Good day. I have created a TreeViewHelper Class in order to trigger events and pass through datacontext to functions. However. Id like to select the treeviewitem when right clicking.

My solution follows the MVVM pattern as close as possible. So if possible i'd like to avoid the Trigger Event feature that is provided.

Id love for some advice on how to tackle this issue.

here is the treeviewhelper.cs class

public static class TreeViewHelper
{
    #region SelectedItem

    public static object GetSelectedItem(DependencyObject obj)
    {
        return (object)obj.GetValue(SelectedItemProperty);
    }

    public static void SetSelectedItem(DependencyObject obj, object value)
    {
        obj.SetValue(SelectedItemProperty, value);
    }

    public static readonly DependencyProperty SelectedItemProperty =
        DependencyProperty.RegisterAttached("SelectedItem", typeof(object), typeof(TreeViewHelper), new UIPropertyMetadata(null, SelectedItemChanged));

    private static void SelectedItemChanged(DependencyObject obj, DependencyPropertyChangedEventArgs dpea)
    {
        if (!(obj is TreeView) || dpea.NewValue == null)
            return;

        var view = obj as TreeView;

        view.SelectedItemChanged += (sender, e) => SetSelectedItem(view, e.NewValue);

        var command = (ICommand)(view as DependencyObject).GetValue(SelectedItemChangedProperty);
        if (command != null)
        {
            if (command.CanExecute(null))
                command.Execute(new DependencyPropertyEventArgs(dpea));
        }
    }

    #endregion

    #region Selected Item Changed

    public static ICommand GetSelectedItemChanged(DependencyObject obj)
    {
        return (ICommand)obj.GetValue(SelectedItemProperty);
    }

    public static void SetSelectedItemChanged(DependencyObject obj, ICommand value)
    {
        obj.SetValue(SelectedItemProperty, value);
    }

    public static readonly DependencyProperty SelectedItemChangedProperty =
        DependencyProperty.RegisterAttached("SelectedItemChanged", typeof(ICommand), typeof(TreeViewHelper));

    #endregion

    #region Event Args

    public class DependencyPropertyEventArgs : EventArgs
    {
        public DependencyPropertyChangedEventArgs DependencyPropertyChangedEventArgs { get; private set; }

        public DependencyPropertyEventArgs(DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
        {
            this.DependencyPropertyChangedEventArgs = dependencyPropertyChangedEventArgs;
        }
    }

    #endregion

}

Here is the XAML Code (shortened)

<TreeView     x:Name="TestPlanTreeView"
              ItemsSource="{Binding Data.TreeViewCollection}"                  
              utils:TreeViewHelper.SelectedItem="{Binding CurrSelItem}"
              utils:TreeViewHelper.SelectedItemChanged="{Binding SelItemChgCmd}">
        <TreeView.ItemContainerStyle>
            <Style TargetType="TreeViewItem">
                <Setter Property="IsSelected" Value="{Binding IsSelected}"/>
                <Setter Property="ContextMenu">
                    <Setter.Value>
                        <ContextMenu ItemsSource="{Binding MenuCollection, RelativeSource={RelativeSource Self}}">
                            <ContextMenu.Resources>
                                <Style TargetType="MenuItem">
                                    <Setter Property="Command" Value="{Binding Command}" />
                                </Style>
                            </ContextMenu.Resources>
                            <ContextMenu.ItemTemplate>
                                <HierarchicalDataTemplate ItemsSource="{Binding Children}">
                                    <TextBlock Text="{Binding Header}"/>
                                </HierarchicalDataTemplate>
                            </ContextMenu.ItemTemplate>
                        </ContextMenu>
                    </Setter.Value>
                </Setter>
            </Style>
        </TreeView.ItemContainerStyle>
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate ItemsSource="{Binding Nodes}">
                <TextBlock Text="{Binding Header}"/>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>

This is how i trigger a function when selecting a new item.

SelItemChgCmd = new RelayCommand<DependencyPropertyEventArgs>(Data.TreeViewItemSelected);
CurrSelItem = new object();

public void TreeViewItemSelected(DependencyPropertyEventArgs dpe)
{
    TreeViewItem selectedTreeViewItem = dpe.DependencyPropertyChangedEventArgs.NewValue as TreeViewItem;
    ListViewCollection = BuildListViewCollection(selectedTreeViewItem);
}      

What I would love to do, is to be able to select the treeviewitem before right clicking on the object. However, I am not sure how to do that with my given code without hacking it.

My original thoughts were to create a property in the treeviewhelper for PreviewRightMouseButtonUp and have that trigger the SelectedItem event, but i then run into issues with data.

Since the PreviewRightMouseButtonUp does not hold the same method types as the selectedItem Changed event, then i run into these data issues.

Id really appreciate some thoughts on this matter. Its been blocking me for a while now.