How to have a column contain multiple users

Question

I have a list with various columns. One of those columns is to store users. However, when I use the code

configurationListFields.Add("Limit_Access_To", SPFieldType.User);

I am only allowed to enter one user. How can I change this so I can enter multiple users or groups?

Answer 1

Here's how you'd do it via code (note: solution does not provide error checking)

using (SPSite siteColl = new SPSite("http://yourSPSite"))
{
    using (SPWeb site = siteColl.OpenWeb())
    {
        SPList customList = site.Lists.TryGetList("Your List Name");
        SPFieldCollection fieldColl = customList.Fields;
        SPFieldUser userField = (SPFieldUser)fieldColl.GetField("ColumnName");
        userField.AllowMultipleValues = true;
        userField.Update();
    }
}

And a slightly shorted version:

using (SPSite siteColl = new SPSite("http://yourSPSite"))
{
    using (SPWeb site = siteColl.OpenWeb())
    {
        SPList customList = site.Lists.TryGetList("Your List Name");
        SPFieldUser userField = (SPFieldUser)customList.Fields["ColumnName"];
        userField.AllowMultipleValues = true;
        userField.Update();
    }
}

Answer 2

Is the column defined to allow multiple values? Go into the list settings, click the person/group column and change the allow multiple selections to Yes.