RegularExpressionValidator.EvaluateIsValid 方法
定义
重要
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指示输入控件中的值是否有效。
protected:
override bool EvaluateIsValid();protected override bool EvaluateIsValid ();override this.EvaluateIsValid : unit -> boolProtected Overrides Function EvaluateIsValid () As Boolean返回
如果输入控件中的值有效，则为 true；否则为 false。
示例
下面的代码示例演示如何重写 EvaluateIsValid 自定义服务器控件中的 方法，以便它始终根据 表达式检查 中的匹配 RegularExpressionValidator项的值。
重要
此示例具有一个接受用户输入的文本框，这是一个潜在的安全威胁。 默认情况下，ASP.NET 网页验证用户输入是否不包含脚本或 HTML 元素。 有关详细信息，请参阅脚本侵入概述。
using System.Web;
using System.Security.Permissions;
namespace Samples.AspNet.CS.Controls
{
[AspNetHostingPermission(SecurityAction.Demand, Level=AspNetHostingPermissionLevel.Minimal)]
public sealed class CustomRegularExpressionValidatorEvaluateIsValid : System.Web.UI.WebControls.RegularExpressionValidator
{
protected override bool EvaluateIsValid()
{
// Get the control to validate's validation value
string controlValue = GetControlValidationValue(this.ControlToValidate);
// If the value is null or empty, then return true
if (controlValue == null || controlValue.Trim().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.ValidationExpression);
return(regExpMatch.Success && regExpMatch.Index == 0 && regExpMatch.Length == controlValue.Length);
}
catch
{
return true;
}
}
}
}
}
Imports System.Web
Imports System.Security.Permissions
Namespace Samples.AspNet.VB.Controls
<AspNetHostingPermission(SecurityAction.Demand, Level:=AspNetHostingPermissionLevel.Minimal)> _
Public NotInheritable Class CustomRegularExpressionValidatorEvaluateIsValid
Inherits System.Web.UI.WebControls.RegularExpressionValidator
Protected Overrides Function EvaluateIsValid() As Boolean
' Get the control to validate's validation value
Dim controlValue As String = GetControlValidationValue(Me.ControlToValidate)
' If the value is null or empty, then return true
If controlValue Is Nothing OrElse controlValue.Trim().Length = 0 Then
Return True
Else
' Else try running the Regular Expression against the value
' and see if there is a match.
Try
Dim regExpMatch As System.Text.RegularExpressions.Match = System.Text.RegularExpressions.Regex.Match(controlValue, Me.ValidationExpression)
Return regExpMatch.Success AndAlso regExpMatch.Index = 0 AndAlso regExpMatch.Length = controlValue.Length
Catch
Return True
End Try
End If
End Function
End Class
End Namespace
下面的代码示例演示如何在 CustomRegularExpressionValidatorEvaluateIsValid Web 窗体页上使用上例中定义的 控件。
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.CS.Controls" Assembly="Samples.AspNet.CS" %>
<%@ Page Language="C#" AutoEventWireup="True" %>
<!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 RegularExpressionValidator - EvaluateIsValid - C# Example</title>
<script runat="server">
void Button1_Click(Object sender, EventArgs e)
{
if (Page.IsValid)
{
Label1.Text = "Page is valid.";
}
else
{
Label1.Text = "Page is invalid!";
}
}
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom RegularExpressionValidator - EvaluateIsValid - C# Example</h3>
<table style="background-color:#eeeeee; padding: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>
<%@ Register TagPrefix="aspSample" Namespace="Samples.AspNet.VB.Controls" Assembly="Samples.AspNet.VB" %>
<%@ Page Language="VB" AutoEventWireup="True" %>
<!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 RegularExpressionValidator - EvaluateIsValid - VB.NET Example</title>
<script runat="server">
Sub Button1_Click(sender As Object, e As EventArgs)
If Page.IsValid Then
Label1.Text="Page is valid."
Else
Label1.Text="Page is not valid!"
End If
End Sub
</script>
</head>
<body>
<form id="Form1" method="post" runat="server">
<h3>Custom RegularExpressionValidator - EvaluateIsValid - VB.NET Example</h3>
<table style="background-color:#eeeeee; padding: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>
