Unity, Custom Menu, in Hierarchy

MyHierarchyMenu.cs

using UnityEngine;
using UnityEditor;
using System.Collections;
 
public class MyHierarchyMenu
{
	[MenuItem("Window/Test/a")]
	static void Test()
	{
	}
 
	[MenuItem("Window/Test/b")]
	static void Test1()
	{
	}
	
	[MenuItem("Window/Test/c/a")]
	static void Test2()
	{
	}
 
 
	[InitializeOnLoadMethod]
	 static void StartInitializeOnLoadMethod()
	 {
	     EditorApplication.hierarchyWindowItemOnGUI += OnHierarchyGUI;
	 }
 
	 static void OnHierarchyGUI(int instanceID, Rect selectionRect)
	 {
	     if (Event.current != null && selectionRect.Contains(Event.current.mousePosition)
	         && Event.current.button == 1 && Event.current.type <= EventType.mouseUp)
	     {
	         GameObject selectedGameObject = EditorUtility.InstanceIDToObject(instanceID) as GameObject;
			 //这里可以判断selectedGameObject的条件
	         if (selectedGameObject)
	         {
				Vector2 mousePosition = Event.current.mousePosition;
 
				EditorUtility.DisplayPopupMenu(new Rect(mousePosition.x, mousePosition.y, 0, 0), "Window/Test",null);
	            Event.current.Use();
	         }			
	     }
	 }
 
}