PowerShell.ps1

function Get-VisualChildren($item) {
	for ($i = 0; $i -lt [System.Windows.Media.VisualTreeHelper]::GetChildrenCount($item); $i++) {
		$child = [System.Windows.Media.VisualTreeHelper]::GetChild($item, $i)
		Get-VisualChildren($child)
	}
	$item
}

function Get-TreeItems {
	Get-VisualChildren $snoopui | ? { $_.GetType().Name -eq "ProperTreeViewItem" }
}

function ShowMessage($treeItem) {
	[system.windows.messagebox]::show($treeItem.ToString());
}
function Set-RightClick($item) {
	#$action = { [system.windows.messagebox]::show($msg) }.GetNewClosure()
	#$action = [ScriptBlock]::Create('[system.windows.messagebox]::show("' + $msg + '")')
	
	#Register-ObjectEvent $item "MouseRightButtonDown" -Action { ShowMessage $Sender; $Event.SourceArgs[1].Handled = $true }
	$handler = [Windows.Input.MouseButtonEventHandler]{ ShowMessage $this; $_.Handled = $true; }
	$item.Add_MouseRightButtonDown($handler)
}

function Show-Message([string]$msg = 'hello world') {
    $action = { [system.windows.messagebox]::show($msg) }.GetNewClosure()
	$action
}

Add-Type @"
    public class DelegateCommand : System.Windows.Input.ICommand
    {
        private System.Action<object> _action;
        public DelegateCommand(System.Action<object> action)
        {
            _action = action;
        }

        public bool CanExecute(object parameter)
        {
            return true;
        }

        public event System.EventHandler CanExecuteChanged = delegate { };

        public void Execute(object parameter)
        {
            _action(parameter);
        }
    }
"@


function Set-ContextMenu() {
	$menuItems = ( @{Item="Add Child Element";Command = New-Object DelegateCommand( { Add-XamlVisual } ) },
		@{Item="Delete";Command = New-Object DelegateCommand( { Delete-Visual } ) } )

	Get-TreeItems | % { 	
		$menu = (New-Object System.Windows.Controls.ContextMenu)
		foreach ($menuItem in $menuItems) {
			$item = New-Object System.Windows.Controls.MenuItem
			$item.Header = $menuItem.Item
			$item.Command = $menuItem.Command
			$menu.Items.Add($item) | Out-Null
		}
		$_.ContextMenu = $menu
	};
}

function Delete-Visual($item = $selected) {
	$parent = $item.parent.visual
	if ($parent.Content) { $parent.Content = $null }
	elseif ($parent.Child) { $parent.Child = $null }
	elseif ($parent.Children) { $parent.Children.Remove($item.visual) }
}

function Add-XamlVisual()
{
	$xaml = Query-Xaml
	Add-Visual($xaml)
}

function Create-Visual([string]$xaml) {
	$pc = (new-object System.Windows.Markup.ParserContext)
	$pc.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation")
	[System.Windows.Markup.XamlReader]::Parse($xaml, $pc)
}

function Add-Visual([string]$xaml, [System.Windows.UIElement]$root = $selected.visual) {
	$visual = Create-Visual $xaml
	try {
		$root.children.add($visual) 
	} catch { }
	try {
		$root.child = $visual 
	} catch { }
	try {
		$root.content = $visual 
	} catch {}
}

function Query-Xaml()
{
	$w = new-object system.windows.window; 
	$w.Width = 400
	$w.Height = 200
	$w.content = new-object system.windows.controls.textbox; 
	$w.content.text = "<TextBlock>Type XAML here!</TextBlock>"; 
	$w.showdialog() | Out-Null
	$w.content.text
}