SPContentTypeUsage Class

[SubsetCallableTypeAttribute]
public sealed class SPContentTypeUsage

using System;
using System.Collections.Generic;
using Microsoft.SharePoint;

namespace Test
{
   class ConsoleApp
   {
      static void Main(string[] args)
      {
         using (SPSite siteCollection = new SPSite("http://localhost"))
         {
            using (SPWeb webSite = siteCollection.OpenWeb())
            {
               // Get the obsolete content type.
               SPContentType obsolete = webSite.ContentTypes["Test"];

               if (obsolete != null) // We have a content type
               {
                  IList<SPContentTypeUsage> usages = SPContentTypeUsage.GetUsages(obsolete);
                  if (usages.Count > 0) // It is in use
                  {
                     Console.WriteLine("The content type is in use in the following locations:");
                     foreach (SPContentTypeUsage usage in usages)
                        Console.WriteLine(usage.Url);
                  }
                  else // It is not in use.
                  {
                     // Delete it.
                     Console.WriteLine("Deleting content type {0}...", obsolete.Name);
                     webSite.ContentTypes.Delete(obsolete.Id);
                  }
               }
               else // No content type is found.
               {
                  Console.WriteLine("The content type does not exist in this site collection.");
               }
            }
         }
         Console.Write("\nPress ENTER to continue...");
         Console.ReadLine();
      }
   }
}