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:

a. Open Visual Studio 2010.

b. Create a console application.

c. Replace the code with the following.

1. using System;

2. using System.Collections.Generic;

3. using System.Linq;

4. using System.Text;

5. using Microsoft.SharePoint;

6. namespace ChangeContentType

7. {

8. class Program   

9. {

10. static void Main(string[] args)       

11. {

12. using (SPSite site = new SPSite("http://serverName:1111/SitePages/Home.aspx"))           

13. {

14. using (SPWeb web = site.RootWeb)               

15. {

16. SPList list = web.Lists["Shared Documents"];

17. SPContentType oldCT = list.ContentTypes["Document"];

18. SPContentType newCT = list.ContentTypes["_CustomContentType"];

19. SPContentTypeId newCTID = newCT.Id;

20. if ((oldCT !=null) && (newCT != null))                   

21. {

22. foreach (SPListItem item in list.Items)                       

23. {

24. if (item.ContentType.Name == oldCT.Name)                           

25. {

26. if (item.File.CheckOutType.ToString() == "None")                                

27. {                                   

28. item.File.CheckOut();                                   

29. item["ContentTypeId"] = newCTID;                                   

30. item.Update();                                   

31. item.File.CheckIn("Checked in");                               

32. }

33. else                               

34. {

35. Console.WriteLine("File " + item.Name + "is checked out to" + item.File.CheckedOutByUser.ToString() + " and cannot be modified");                               

36. }                           

37. }

38. else                           

39. {

40. Console.WriteLine("File "+item.Name+ " is associated with the content type "+ item.ContentType.Name+ " and shall not be modified");                           

41. }                       

42. }                   

43. }

44. else                   

45. {

46. Console.WriteLine("One of the content types specified has not been attached to the list "+list.Title);                   

47. }

48. Console.ReadLine();               

49. }           

50. }       

51. }   

52. }

53. }
    

d. Hit F5.