In my searching for how to do this, I have found that ms doesn't want you to use the user_id, they want you to use the loginName. In any case, I just need to add the loginName of the current user to a table when an insert is performed, here is what I have currently.
In the codebehind
protected void FormView1_ItemInserting(Object sender, System.Web.UI.WebControls.FormViewInsertEventArgs e)
e.Values["CustLogin"] = User.Identity.Name;
but this isn't working.
I don't know if there is a better way to do this, perhaps without using the codebehind, but any help would be appreciated.