Question

We have an UI where user selects a department. It goes into a List item. We have separate SharePoint user groups for each department.

I want to populate the users in the SharePoint group in one of the list Item. So now based on department selected I need to populate the List Item.

Please help me in doing this. I am able to get all the users in a group using:

        DropDownList ddl = new DropDownList();
        ArrayList al = new ArrayList();
        SPWeb web = SPContext.Current.Web;
        SPGroupCollection grpCln = web.Groups;
        foreach (SPGroup grp in grpCln)
        {
            if (grp.Name == "Viewers")
            {
                foreach (SPUser user in grp.Users)
                {
                    al.Add(user.Name);
                }
            }
        }
        ddl.DataSource = al;
        ddl.DataBind();

Answer 1

I asked you in the comments, but the solution to these cases are usually Custom List Field Iterators to override your actual “Users” control, or you can also add a custom site column and hook it to your list dynamically filtering its content when rendering.