I have a "person or group" type column in my calendar list as "Participants". I need to add and remove users from this column. Adding users works fine. When trying to remove a user it does not get removed. The code is:

SPListItem item = myList.GetItemById(itemId);
string usersOfItem = item["Participants"].ToString();
SPFieldUserValueCollection participants = new SPFieldUserValueCollection(web, usersOfItem);

//user login i get from a querystring
SPUser user = web.SiteUsers[login];
SPFieldUserValue userFUValue=new SPFieldUserValue(web, user.ID, user.Name);

// Below line executes with no error but user is not removed

item["Participants"] = participants;


I tried SPFieldUserValue userFUValue=new SPFieldUserValue(web, user.ID, user.LoginName); instead of user.Name but login name does not work as during debugging i see loginName gives the below value


Which does not match with the user displayed in SPFieldUserValueCollection . The user inside the collection is displayed in the foramt : "ID;firstname lastname" Eg:

1;#Franklin Dixon

When SPFieldUserValue userFUValue=new SPFieldUserValue(web, user.ID, user.Name); is used, the two user field's matches, the code runs with no error. But user is not removed. . The user is available in the participants SPFieldUserValueCollection after Remove() is executed. Am i missing any point here ?

1 Answer 1


Use following code:

private static void DeleteUserFromList(SPUser userDeleted, string fieldName, SPListItem item, SPWeb sPWeb)
    SPFieldUserValueCollection Users = (SPFieldUserValueCollection)item[fieldName];
    SPFieldUserValue DeletedUserValue = Users.First(u => u.LookupId == userDeleted.ID);
    item[fieldName] = Users;
  • Great ! Works like a charm !!
    – Shaamil
    Commented Oct 9, 2014 at 12:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.