Notes:
Web Page
<%@ Page Language="C#" %>
<html>
<head>
<title>Check a field for a positive numeric value</title>
</head>
<body>
<h2>Enter a positive number</h2>
<form method="post" Runat="server">
<asp:TextBox ID="field" Runat="server" />
<asp:RangeValidator ControlToValidate="field"
MinimumValue="0" MaximumValue="2000000000" Type="Integer"
Text="must be a positive number"
Runat="server" />
</form>
</body>
</html>