CompareValidator.EvaluateIsValid Method
.NET Framework 3.0
This method supports the .NET Framework infrastructure and is not intended to be used directly from your code.
When overridden in a derived class, this method contains the code to determine whether the value in the input control is valid.
Namespace: System.Web.UI.WebControlsAssembly: System.Web (in system.web.dll)
The following code example demonstrates how to override the EvaluateIsValid method in a custom server control so that it always returns true if the values of the two specified controls are the same and false otherwise.
Security Note: |
|---|
| This example has a text box that accepts user input, which is a potential security threat. By default, ASP.NET Web pages validate that user input does not include script or HTML elements. For more information, see Script Exploits Overview (Visual Studio). |
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet" Assembly="Samples.AspNet.JSL" %>
<%@ Page language="VJ#" %>
<!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>
<title>Custom CompareValidator - EvaluateIsValid - VJ# Example</title>
<script runat="server">
void Page_Load(Object sender, EventArgs e)
{
// Run the Page Validate method in order to force
// the CompareValidate to show it's error message.
get_Page().Validate();
} //Page_Load
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom CompareValidator - EvaluateIsValid - VJ# Example</h3>
<asp:TextBox id="TextBox1" runat="server" Text="123"></asp:TextBox><br />
<asp:TextBox id="TextBox2" runat="server" Text="123"></asp:TextBox>
<aspSample:CustomCompareValidatorEvaluateIsValid
id="CompareValidator1"
runat="server"
ErrorMessage="Value in TextBox2 does not match value in TextBox1."
Display="Dynamic"
ControlToCompare="TextBox2"
ControlToValidate="TextBox1" /><br />
<asp:Button id="Button1" runat="server" Text="Button" />
</form>
</body>
</html>
...
package Samples.AspNet;
public class CustomCompareValidatorEvaluateIsValid
extends System.Web.UI.WebControls.CompareValidator
{
protected boolean EvaluateIsValid()
{
// Get the values from the two controls
String controlToValidateValue = this.GetControlValidationValue(
this.get_ControlToValidate());
String controlToCompareValue = this.GetControlValidationValue(
this.get_ControlToCompare());
// If the values are the same, return true, else return false.
if (System.String.Compare(controlToValidateValue, 0,
controlToCompareValue, 0, controlToCompareValue.get_Length(),
false, System.Globalization.CultureInfo.get_InvariantCulture()) ==
0) {
return true;
}
else {
return false;
}
} //EvaluateIsValid
} //CustomCompareValidatorEvaluateIsValid
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