//protected Label LabelRegularExpression;
        public void InitializeWithField(SPField field)
        {
            this.fldCustomFieldTypeRegEx = field as CustomFieldTypeRegEx;

            if (this.Page.IsPostBack)
            {
                return;
            }

            txtRegularExpression.Text = "";
            txtErrorMessage.Text = "";

            if (field != null)
            {
                txtRegularExpression.Text = fldCustomFieldTypeRegEx.propRegularExpression;
                txtErrorMessage.Text = fldCustomFieldTypeRegEx.propErrorMessage;
                //this.txtRegularExpression.Visible = true;
            }
            else
            {
                txtRegularExpression.Text = "";
                txtRegularExpression.Text = "";
                //this.txtRegularExpression.Visible = true;
            }
        }
        //protected Label LabelRegularExpression;

        public void InitializeWithField(SPField field)
        {
            this.fldCustomFieldTypeRegEx = field as CustomFieldTypeRegEx;

            if (this.Page.IsPostBack)
            {
                return;
            }

            txtRegularExpression.Text = "";
            txtErrorMessage.Text      = "";


            if (field != null)
            {
                txtRegularExpression.Text = fldCustomFieldTypeRegEx.propRegularExpression;
                txtErrorMessage.Text      = fldCustomFieldTypeRegEx.propErrorMessage;
                //this.txtRegularExpression.Visible = true;
            }
            else
            {
                txtRegularExpression.Text = "";
                txtRegularExpression.Text = "";
                //this.txtRegularExpression.Visible = true;
            }
        }
        public void OnSaveChange(SPField field, bool bNewField)
        {
            CustomFieldTypeRegEx lookup = (CustomFieldTypeRegEx)field;

            lookup.IsNew = bNewField;
            lookup.propRegularExpression = this.txtRegularExpression.Text;
            lookup.propErrorMessage      = this.txtErrorMessage.Text;
        }