How to delete a custom columns from a content-type in Sharepoint Client object model

Question

I have a windows interface where I create a content-type and then create a column and adds that column to the content-type.
//availableCT is my content-type where the column is present.
//get all available fields within this content-type
FieldCollection fieldColl = availableCT.Fields;
clientContext.Load(fieldColl);
clientContext.ExecuteQuery();
foreach (Field field in fieldColl)
//columnFromList is the column that is to be deleted
if (field.InternalName.Equals(columnFromList))
field.DeleteObject();
clientContext.ExecuteQuery(); // this throws an exception
// Additional information: Site columns which are included in content types or on lists cannot be deleted. Please remove all instances of this site column prior to deleting it.

Answer 1

hi,
you can use the below code to delete it
using (ClientContext sourceContext = new ClientContext(cmdSpoSite))
Web web = sourceContext.Web;
sourceContext.Load(web);
sourceContext.Load(web.AvailableContentTypes, type => type.Include(c => c.FieldLinks, c => c.Name));
sourceContext.ExecuteQuery();
List<ContentType> ExistingContentType = web.AvailableContentTypes.ToList();
IEnumerable<ContentType> contentTypesList = ExistingContentType.Where(ct => ct.Name == "<ContentTypeName>");
ContentType ctype = contentTypesList.ElementAt(0);
IQueryable<FieldLink> flinks = ctype.FieldLinks.Where(f => f.Name == "<FiledName");
foreach (FieldLink flink in flinks)
flink.DeleteObject();
ctype.Update(true);
sourceContext.ExecuteQuery();
The difference being in your code and above code is you are removeing fileds which is eventually is deleting site column but a site column cannot be deleted if is alreday being used. So you need to deled the FieldLink in content type taht way column is removed
from content type but not from site column.
Now if you want to delete site column you can use your code to deleted Field.
Whenever you see a reply and if you think is helpful,Vote As Helpful! And whenever you see a reply being an answer to the question of the thread, click Mark As Answer