CompareValidator.EvaluateIsValid Method ()
.NET Framework (current version)
This API supports the product 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.
Assembly: 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
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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. |
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %> <%@ Page language="VB" %> <!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 - VB.NET Example</title> </head> <body> <form id="Form1" method="post" runat="server"> <h3>Custom CompareValidator - EvaluateIsValid - C# Example</h3> <asp:TextBox id="TextBox1" runat="server">123</asp:TextBox><br /> <asp:TextBox id="TextBox2" runat="server">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>
Imports System.Web Imports System.Security.Permissions Namespace Samples.AspNet.VB.Controls <AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _ Public NotInheritable Class CustomCompareValidatorEvaluateIsValid Inherits System.Web.UI.WebControls.CompareValidator Protected Overrides Function EvaluateIsValid() As Boolean ' Get the values from the two controls Dim controlToValidateValue As String = Me.GetControlValidationValue(Me.ControlToValidate) Dim controlToCompareValue As String = Me.GetControlValidationValue(Me.ControlToCompare) ' If the values are the same, return true, else return false. If (System.String.Compare(controlToValidateValue, 0, controlToCompareValue, 0, controlToCompareValue.Length, False, System.Globalization.CultureInfo.InvariantCulture) = 0) Then Return True Else Return False End If End Function End Class End Namespace
.NET Framework
Available since 1.1
Available since 1.1
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