Revit二次开发中管道生成三通——两管生成和三管生成

 using Autodesk.Revit.DB;

    
 using Autodesk.Revit.UI;
    
 using Autodesk.Revit.UI.Selection;
    
 using Autodesk.Revit.Attributes;
    
 using System.Linq;
    
 using System.Collections.Generic;
    
 using Autodesk.Revit.DB.Mechanical;
    
 using System;
    
 using System.Windows;
    
 using Autodesk.Revit.DB.Plumbing;
    
  
    
 namespace WPF_srqc
    
 {
    
     [Transaction(TransactionMode.Manual)]
    
     class NewTeeFitting : IExternalCommand
    
     {
    
     public Result Execute(ExternalCommandData commandDat