在GridView验证时,提示行号

<pbcrm:PBCRMGridView ID="gvCustomer" runat="server" 
                    AllowPaging="false" AllowSorting="false"
                    EnableViewState="false" DataSourceID="sqldsClientList"  
                    DataKeyNames="HolderKey"                     
                    AutoGenerateColumns="False" Width="99%">
                    <Columns>                      
                       <asp:BoundField DataField="CustomerName" HeaderText="Client Name" ReadOnly="True" SortExpression="CustomerName" />
                      <asp:BoundField DataField="Nationality" HeaderText="Nationality" ReadOnly="True" SortExpression="Nationality" />
                      <asp:BoundField DataField="YearofBirth" HeaderText="Year of Birth" ReadOnly="True" SortExpression="YearofBirth" />
                      <asp:BoundField DataField="Age" HeaderText="Age" ReadOnly="True"  SortExpression="Age" />
                      <asp:BoundField DataField="IsPI" HeaderText="PI Status" SortExpression="IsPI" />            
                      <asp:TemplateField>
                            <headertemplate>
                                Education Level
                            </headertemplate>
                            <itemtemplate>                                
                                <pbcrm:EducationLevelDDL  ID="ddlEduLevel" runat="server" 
                                    SelectedValue='<%#Eval("EduLevel") %>'/>
                                <pbcrm:PBCRMRequiredFieldValidator ID="rfvEduLevel"  
                                        ControlToValidate="ddlEduLevel"                                         
                                        ErrorMessage= '<%#"Education Level for client " + (Container.DataItemIndex + 1).ToString() + " is required"%>'
                                        runat="server"  Display="None"/>
                            </itemtemplate>                            
                        </asp:TemplateField>
                        
                        <asp:TemplateField>
                            <headertemplate>
                                Visually Impaired
                            </headertemplate>
                            <itemtemplate>                                
                                <pbcrm:VisuallyImpairedDDL ID="ddlVisualImp" runat="server" 
                                  SelectedValue='<%#Eval("VisualImp") %>'/>
                                <pbcrm:PBCRMRequiredFieldValidator ID="rfvVisualImp"  
                                        ControlToValidate="ddlVisualImp" 
                                        ErrorMessage= '<%#"Visually Impaired for client " + (Container.DataItemIndex + 1).ToString() + " is required"%>'
                                        runat="server"  Display="None"/>
                            </itemtemplate>                           
                        </asp:TemplateField>                      
                    </Columns>
                </pbcrm:PBCRMGridView>