//Return properly validated and added users

private SPFieldUserValueCollection UserValidation(SPWeb web, string Users)

{

SPFieldUserValueCollection userCollection = new SPFieldUserValueCollection();

string FormatedUsers = string.Empty;

string[] UserArray = Users.Split(';');

foreach (string sUser in UserArray)

{

SPUser user = null;

try

{

user = web.AllUsers[sUser];

}

catch { }

if (user == null)

{

try

{

web.AllUsers.Add(sUser, "", sUser, "");

web.Update();

user = web.AllUsers[sUser];

}

catch { }

}

if (user != null)

{

userCollection.Add(new SPFieldUserValue(web, user.ID, user.LoginName));

}

}

return userCollection;

}

}

public void UpdateMyList()

{

try

{

//Should do something like:

//string TopLevelSite = ConfigurationSettings.AppSettings["Site"];

string TopLevelSite = "http://r2-basemachine:1111";

using (SPSite SPSSite = new SPSite(TopLevelSite))

{

using (SPWeb sPWeb = SPSSite.OpenWeb())

{

string listName = "DatasheetTest";

SPList list = null;

DataTable dt = null;

SPListItemCollection listCol = null;

list = sPWeb.Lists[listName];

listCol = list.Items;

dt = listCol.GetDataTable();

foreach (DataRow dr in dt.Rows)

{

SPFieldUserValueCollection userCollection = new SPFieldUserValueCollection();

userCollection = UserValidation(sPWeb, dr["Multi"].ToString());

SPListItem ListItem = list.GetItemById((int)dr["Id"]);

ListItem["PersonField"] = userCollection;

ListItem.Update();

}

}

}

}

catch (Exception ex)

{

Console.WriteLine("Error: " + ex.ToString());

}

}