<asp:TextBox ID="txtProva" runat="server"></asp:TextBox>
    <asp:RangeValidator runat="server" ID="RangeProva" ErrorMessage="Errore!" ControlToValidate="txtProva" MinimumValue="0" MaximumValue="10" Type="Integer"></asp:RangeValidator>
    <asp:Button ID="btnProva" runat="server" Text="premi qui" />