validation for intger more than zwro

 <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
        <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1"
            ErrorMessage="Required Field " Display="Dynamic"></asp:RequiredFieldValidator>
        <asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="TextBox1"
            ValidationExpression="^[0-9]*$" Display="Dynamic" ErrorMessage="RegularExpressionValidator"></asp:RegularExpressionValidator>
        <asp:CompareValidator ID="CompareValidator1" ValueToCompare="0" Type="Integer" ControlToValidate="TextBox1"
            Operator="GreaterThan" runat="server" Display="Dynamic" ErrorMessage="Compare Validator"></asp:CompareValidator>
        <asp:Button ID="Button1" runat="server" Text="Button" />