CompareValidator performs three different types of validations : CompareValidator « Validation « ASP.NET Tutorial

A data type check
Compare the value against a fixed value
Compare the value against another


Important properties

ControlToValidate: The ID of the form field being validated.

Text:              The error message.

Type:              The type of value being compared. 
                   Possible values are String, Integer, Double, Date, and Currency.

Operator:          The type of comparison to perform. 
                   Possible values are DataTypeCheck, Equal, GreaterThan, GreaterThanEqual, LessThan, LessThanEqual, and NotEqual.

ValueToCompare:    The fixed value.

ControlToCompare:  The ID of a control against which to compare.


<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show Data Type Check</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

    <asp:Label
        id="lblBirthDate"
        Text="Birth Date:"
        AssociatedControlID="txtBirthDate"
        Runat="server" />
    <asp:TextBox
        id="txtBirthDate"
        Runat="server" />
    <asp:CompareValidator
        id="cmpBirthDate"
        Text="(Invalid Date)"
        ControlToValidate="txtBirthDate"
        Type="Date"
        Operator="DataTypeCheck"
        Runat="server" />

    <br /><br />

    <asp:Button
        id="btnSubmit"
        Text="Submit"
        Runat="server" />

    </div>
    </form>
</body>
</html>

8.2.CompareValidator
	8.2.1.	CompareValidator performs three different types of validations
	8.2.2.	CompareValidator performs a comparison against a fixed value.
	8.2.3.	CompareValidator compares the value of one form field against another form field.
	8.2.4.	asp:CompareValidator, Type='String', Operator='NotEqual' and ErrorMessage
	8.2.5.	What happens to asp:CompareValidator in the client side
	8.2.6.	Set DeleteParameters, InsertParameters and UpdateParameters for asp:SqlDataSource
	8.2.7.	Using the CompareValidator to test values against other control values
	8.2.8.	Using the CompareValidator to validate against constants
	8.2.9.	To specify the data types: Currency, Date, Double, Integer, String
	8.2.10.	Making comparisons with the CompareValidator control
	8.2.11.	CompareValidator for number, text and password
	8.2.12.	Disable Client Validation
	8.2.13.	Use CompareValidator to check password field and confirm password field
	8.2.14.	CompareValidator with age field
	8.2.15.	Check birthday