RegularExpressionValidator.EvaluateIsValid Method
.NET Framework 2.0
Indicates whether the value in the input control is valid.
Namespace: System.Web.UI.WebControls
Assembly: System.Web (in system.web.dll)
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 checks the value against the expression for a match in a RegularExpressionValidator.
package Samples.AspNet.JSL.Controls;
public class CustomRegularExpressionValidatorEvaluateIsValid
extends System.Web.UI.WebControls.RegularExpressionValidator
{
protected boolean EvaluateIsValid()
{
// Get the control to validate's validation value
String controlValue = GetControlValidationValue(this.
get_ControlToValidate());
// If the value is null or empty, then return true
if (controlValue == null || controlValue.Trim().get_Length() == 0) {
return true;
}
else {
// Else try running the Regular Expression against the value
// and see if there is a match.
try {
System.Text.RegularExpressions.Match regExpMatch
= System.Text.RegularExpressions.Regex.Match(controlValue,
this.get_ValidationExpression());
return regExpMatch.get_Success()
&& regExpMatch.get_Index() == 0
&& regExpMatch.get_Length() == controlValue.get_Length();
}
catch (System.Exception exp) {
return true;
}
}
} //EvaluateIsValid
} //CustomRegularExpressionValidatorEvaluateIsValid
The following code example demonstrates how to use the CustomRegularExpressionValidatorEvaluateIsValid control, defined in the preceding example, on a Web Forms page.
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.JSL.Controls" Assembly="Samples.AspNet.JSL" %>
<%@ Page Language="VJ#" AutoEventWireup="True" %>
<HTML>
<HEAD>
<title>Custom RegularExpressionValidator - EvaluateIsValid - VJ# Example</title>
<script runat="server">
void Button1_Click(Object sender, EventArgs e)
{
if (get_Page().get_IsValid()) {
Label1.set_Text("Page is valid.");
}
else {
Label1.set_Text("Page is invalid!");
}
} //Button1_Click
</script>
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom RegularExpressionValidator - EvaluateIsValid - VJ# Example</h3>
<table bgcolor="#eeeeee" cellpadding="10">
<tr valign="top">
<td colspan="3">
<asp:Label ID="Label1"
Text="Enter a 5 digit zip code"
runat="server"/>
</td>
</tr>
<tr>
<td colspan="3">
<b>Personal Information</b>
</td>
</tr>
<tr>
<td align="right">
Zip Code:
</td>
<td>
<asp:TextBox id="TextBox1" runat="server"/>
</td>
<td>
<aspSample:CustomRegularExpressionValidatorEvaluateIsValid
id="Regularexpressionvalidator1"
runat="server"
ControlToValidate="TextBox1"
ValidationExpression="\d{5}"
ErrorMessage="Zip code must be 5 numeric digits"
Display="Static"
EnableClientScript="False" />
</td>
</tr>
<tr>
<td></td>
<td>
<asp:Button text="Button1"
OnClick="Button1_Click"
runat=server ID="Button1"/>
</td>
<td></td>
</tr>
</table>
</form>
</body>
</HTML>
Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
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