public static void Update(FormUser formUser)
{
List<FormUser> formsUsers2 = GetFormsUsers(formUser.FormID, formUser.UserID);
if (formsUsers2 != null && formsUsers2.Count > 0 && formsUsers2[0].ID != formUser.ID)
throw new Exception("This user already exists, please choose another user");
FormUserDataMapper.Update(formUser);
}