RequiredFieldValidator: require a user to enter a value in a form field. RangeValidator: check whether a value falls between a certain minimum and maximum value. CompareValidator: compare a value against another value or perform a data type check. RegularExpressionValidator: compare a value against a regular expression. CustomValidator: perform custom validation. ValidationSummary: display a summary of all validation errors in a page. <%@ Page Language="C#" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <script runat="server"> void btnSubmit_Click(Object sender, EventArgs e) { if (Page.IsValid) { lblResult.Text = @"<br />Product: " + txtProductName.Text + "<br />Price: " + txtProductPrice.Text + "<br />Quantity: " + txtProductQuantity.Text; } } </script> <html xmlns="http://www.w3.org/1999/xhtml" > <head id="Head1" runat="server"> <title>Order Form</title> </head> <body> <form id="form1" runat="server"> <div> <fieldset> <legend>Order Form</legend> <asp:Label id="lblProductName" Text="Product Name:" AssociatedControlID="txtProductName" Runat="server" /> <br /> <asp:TextBox id="txtProductName" Runat="server" /> <asp:RequiredFieldValidator id="reqProductName" ControlToValidate="txtProductName" Text="(Required)" Runat="server" /> <br /><br /> <asp:Label id="lblProductPrice" Text="Product Price:" AssociatedControlID="txtProductPrice" Runat="server" /> <br /> <asp:TextBox id="txtProductPrice" Columns="5" Runat="server" /> <asp:RequiredFieldValidator id="reqProductPrice" ControlToValidate="txtProductPrice" Text="(Required)" Display="Dynamic" Runat="server" /> <asp:CompareValidator id="cmpProductPrice" ControlToValidate="txtProductPrice" Text="(Invalid Price)" Operator="DataTypeCheck" Type="Currency" Runat="server" /> <asp:Label id="lblProductQuantity" Text="Product Quantity:" AssociatedControlID="txtProductQuantity" Runat="server" /> <br /> <asp:TextBox id="txtProductQuantity" Columns="5" Runat="server" /> <asp:RequiredFieldValidator id="reqProductQuantity" ControlToValidate="txtProductQuantity" Text="(Required)" Display="Dynamic" Runat="server" /> <asp:CompareValidator id="CompareValidator1" ControlToValidate="txtProductQuantity" Text="(Invalid Quantity)" Operator="DataTypeCheck" Type="Integer" Runat="server" /> <asp:Button id="btnSubmit" Text="Submit Product Order" OnClick="btnSubmit_Click" Runat="server" /> </fieldset> <asp:Label id="lblResult" Runat="server" /> </div> </form> </body> </html>