Losing formatted ErrorMessage on RequiredFieldValidator

[DigiSoft]

I have a RequiredFieldValidator for a textbox within a gridview that I'm trying to set the ErrorMessage on in code. When debugging, the code seems to be formatting the ErrorMessage ok, however when the validator fires, I get the unformatted ErrorMessage.\[code\]<asp:CheckBox ID="chkExclusion" runat="server" AutoPostBack="true" Checked='<%# DataBinder.Eval(Container.DataItem, "Exclusion") %>' Text='<%# DataBinder.Eval(Container.DataItem, "Name") %>' OnCheckedChanged="gvExclusions_CheckChanged"<asp:TextBox ID="txtEffectiveDate" runat="server" Width="75px" MaxLength="10" CssClass="jQueryUIDatePicker" Text='<%# DataBinder.Eval(Container.DataItem, "EffDateString") %>' Enabled="false" /><asp:Label ID="lblEffectiveDateRequired" runat="server" CssClass="RequiredField" Visible="false">*</asp:Label><br /><span class="UnderTextBox" style="width: 80px;"><asp:Label ID="lblEffectiveDateFormat" runat="server" Text="mm/dd/yyyy" CNFKey="MMDDYYYY" /></span><asp:RequiredFieldValidator runat="server" ID="rfvEffectiveDate" ControlToValidate="txtEffectiveDate" Display="None" ValidationGroup="NewEnrolment" Enabled="false" ErrorMessage="Please enter the Effective Date for {0}." />\[/code\]I try to override the ErrorMessage in the RowDataBound of the gridview:\[code\]Private Sub gvExclusions_RowDataBound(sender As Object, e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvExclusions.RowDataBound If e.Row.RowType = DataControlRowType.DataRow Then Dim chk As CheckBox = CType(e.Row.FindControl("chkExclusion"), CheckBox) Dim rfv As RequiredFieldValidator = CType(e.Row.FindControl("rfvEffectiveDate"), RequiredFieldValidator) rfv.ErrorMessage = String.Format(rfv.ErrorMessage, chk.Text) End IfEnd Sub\[/code\]When I debug, I can see that the rfv.ErrorMessage is set correctly, however when I trip the validator at runtime, I get the unformatted message of "Please enter the Effective Date for {0}." rather than "Please enter the Effective Date for BOB."I have this all in an UpdatePanel and enable/disable the validators depending on the status of the checkbox as follows:\[code\]Protected Sub gvExclusions_CheckChanged(sender As Object, e As System.EventArgs) Dim chk As CheckBox = CType(sender, CheckBox) Dim row As GridViewRow = CType(chk.Parent.Parent, GridViewRow) Dim rfv As RequiredFieldValidator = CType(row.FindControl("rfvEffectiveDate"), RequiredFieldValidator) Dim lbl As Label = CType(row.FindControl("lblEffectiveDateRequired"), Label) Dim txt As TextBox = CType(row.FindControl("txtEffectiveDate"), TextBox) rfv.Enabled = chk.Checked lbl.Visible = chk.Checked txt.Enabled = chk.CheckedEnd Sub\[/code\]