How to change the content type for files in SharePoint

In this article we will be seeing how to change a batch of files in a document library from one content type to another using C#.

I have batch of files in a document library which belongs to the "Document "content type. I want to change the content type from "Document" to "_CustomContentType (which is a custom content type).



Steps Involved:

• Open Visual Studio 2010.
• Create a console application.
• Replace the code with the following.
  
  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using Microsoft.SharePoint;

  namespace ChangeContentType
  {
      class Program
      {
          static void Main(string[] args)
          {
              using (SPSite site = new SPSite("http://serverName:1111/SitePages/Home.aspx"))
              {
                  using (SPWeb web = site.RootWeb)
                  {
                      SPList list = web.Lists["Shared Documents"];
                      SPContentType oldCT = list.ContentTypes["Document"];
                      SPContentType newCT = list.ContentTypes["_CustomContentType"];
                      SPContentTypeId newCTID = newCT.Id;
                      if ((oldCT != null) && (newCT != null))
                      {
                          foreach (SPListItem item in list.Items)
                          {
                              if (item.ContentType.Name == oldCT.Name)
                              {
                                  if (item.File.CheckOutType.ToString() == "None")
                                  {
                                      item.File.CheckOut();
                                      item["ContentTypeId"] = newCTID;
                                      item.Update();
                                      item.File.CheckIn("Checked in");
                                  }
                                  else
                                  {
                                      Console.WriteLine("File " + item.Name + "is checked out to" + item.File.CheckedOutByUser.ToString() + " and
  cannot be modified");
                                  }
                              }
                              else
                              {
                                      Console.WriteLine("File "+item.Name+ " is associated with the content type "+ item.ContentType.Name+ " and
  shall not be modified");
                              }
                          }
                      }
                      else
                      {
                          Console.WriteLine("One of the content types specified has not been attached to the list "+list.Title);
                      }
                      Console.ReadLine();
                  }
              }
          }
      }
  }
  
  • Hit F5.