DataCogsFieldControls 有时保存不上的问题

        public void InitializeWithField(SPField field)
        {
            if (!IsPostBack)
            {
                ChildDropDownListField ChildField = field as ChildDropDownListField;
                if (ChildField != null)
                {
                    childSiteUrl = ChildField.ChildSiteUrl;
                    childListName = ChildField.ChildListName;
                    childListTextField = ChildField.ChildListTextField;
                    childListValueField = ChildField.ChildListValueField;
                    childJoinField = ChildField.ChildJoinField;

                    EnsureChildControls();

                    if (string.IsNullOrEmpty(txtSiteURL.Text) && !string.IsNullOrEmpty(childSiteUrl))
                    {
                        txtSiteURL.Text = childSiteUrl;
                        loadLists();
                        ddlLists.Items.FindByText(childListName).Selected = true;
                        refreshLookups();
                        ddlColumnText.Items.FindByText(childListTextField).Selected = true;
                        ddlColumnValue.Items.FindByText(childListValueField).Selected = true;
                        ddlColumnJoin.Items.FindByText(childJoinField).Selected = true;
                    }
                }
            }
        }