Gracias por la respuesta.
Lo puse fuera del Grid, ya que dentro del mismo me da error. Dice que no conoce validator.
Este es el código:
Código:
<asp:GridView ID="GridView1" runat="server" DataSourceID="ObjectDataSource1"
AutoGenerateColumns="False" AllowPaging="True"
onselectedindexchanged="GridView1_SelectedIndexChanged"
AutoGenerateDeleteButton="True" AutoGenerateEditButton="True" CellPadding="4"
ForeColor="#333333" GridLines="None">
<AlternatingRowStyle BackColor="White" />
<Columns>
<asp:TemplateField HeaderText="#" SortExpression="id">
<%-- <EditItemTemplate>
<asp:TextBox Width="4" ID="TextBox1" ReadOnly="true" runat="server" Text='<%# Bind("id") %>'></asp:TextBox>
</EditItemTemplate>--%>
<ItemTemplate>
<asp:Label Width="4" Enabled="false" ID="Label1" runat="server" Text='<%# Bind("id") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Razon Social" SortExpression="razonSocial">
<EditItemTemplate>
<asp:TextBox ID="TextBoxRazonSocial" runat="server" Text='<%# Bind("razonSocial") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label3" runat="server" Text='<%# Bind("razonSocial") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Provincia" SortExpression="Provincia">
<EditItemTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
DataSourceID="ObjectDataSourceProvincia"
DataTextField="Nombre" DataValueField="IdProvincia" selectedValue='<%# Bind("idProvincia")%>'>
</asp:DropDownList>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label4" runat="server" Text='<%# Bind("Provincia.Nombre") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Localidad" SortExpression="localidad">
<EditItemTemplate>
<asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("localidad") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label4" runat="server" Text='<%# Bind("localidad") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Direccion" SortExpression="direccion">
<EditItemTemplate>
<asp:TextBox ID="TextBox5" runat="server" Text='<%# Bind("direccion") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label6" runat="server" Text='<%# Bind("direccion") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="CodPostal" SortExpression="codPostal">
<EditItemTemplate>
<asp:TextBox Width="10" ID="TextBox6" runat="server" Text='<%# Bind("codPostal") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label7" runat="server" Text='<%# Bind("codPostal") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="IVA" SortExpression="iva">
<EditItemTemplate>
<asp:DropDownList ID="DropDownListIVA" runat="server" DataSourceID="ObjectDataSourceIVA" DataTextField="IVA" DataValueField="idIVA" selectedValue='<%# Bind("idIva")%>'
>
</asp:DropDownList>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label5" runat="server" Text='<%# Bind("IVA.iva") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField HeaderText="Fecha alta" SortExpression="fecha">
<EditItemTemplate>
<asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("fecha") %>'></asp:TextBox>
</EditItemTemplate>
<ItemTemplate>
<asp:Label ID="Label2" runat="server" Text='<%# Bind("fecha") %>'></asp:Label>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField DataField="estado" HeaderText="Estado"
SortExpression="estado" />
</Columns>
<EditRowStyle BackColor="#2461BF" />
<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
<RowStyle BackColor="#EFF3FB" />
<SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />
<SortedAscendingCellStyle BackColor="#F5F7FB" />
<SortedAscendingHeaderStyle BackColor="#6D95E1" />
<SortedDescendingCellStyle BackColor="#E9EBEF" />
<SortedDescendingHeaderStyle BackColor="#4870BE" />
</asp:GridView>
<asp:ObjectDataSource ID="ObjectDataSourceIVA" runat="server"
SelectMethod="getALL" TypeName="BLL.GestorIVA">
</asp:ObjectDataSource>
<asp:ObjectDataSource ID="ObjectDataSourceProvincia" runat="server"
SelectMethod="getAll" TypeName="BLL.GestorProvincia"></asp:ObjectDataSource>
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
SelectMethod="getAll" TypeName="BLL.GestorClientes"
DataObjectTypeName="BE.Cliente" UpdateMethod="update">
</asp:ObjectDataSource>
<%--
Validators *****************************************************************
--%>
<asp:RequiredFieldValidator runat="server" ControlToValidate= "TextBoxRazonSocial" ErrorMessage="RequiredFieldValidator"></asp:RequiredFieldValidator>"
Muchas gacias nuevamente