更新：2007 年 11 月
命名空間：
System.Web.UI.WebControls 組件：
System.Web (在 System.Web.dll 中)
<AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
<AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level := AspNetHostingPermissionLevel.Minimal)> _
Public Class RequiredFieldValidator _
Inherits BaseValidator
Dim instance As RequiredFieldValidator
[AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal)]
public class RequiredFieldValidator : BaseValidator
[AspNetHostingPermissionAttribute(SecurityAction::InheritanceDemand, Level = AspNetHostingPermissionLevel::Minimal)]
[AspNetHostingPermissionAttribute(SecurityAction::LinkDemand, Level = AspNetHostingPermissionLevel::Minimal)]
public ref class RequiredFieldValidator : public BaseValidator
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.InheritanceDemand, Level = AspNetHostingPermissionLevel.Minimal) */
/** @attribute AspNetHostingPermissionAttribute(SecurityAction.LinkDemand, Level = AspNetHostingPermissionLevel.Minimal) */
public class RequiredFieldValidator extends BaseValidator
public class RequiredFieldValidator extends BaseValidator
<asp:RequiredFieldValidator />
使用這個控制項讓輸入控制項成為必要的欄位。如果輸入控制項在遺失焦點時沒有從 InitialValue 屬性變更其數值，就無法通過驗證。
多個驗證器可以和同一個輸入控制項產生關聯。例如，RequiredFieldValidator 可用來確認控制項的輸入，而同時 RangeValidator 可用來確認輸入是在指定的資料範圍內。
如需驗證控制項的額外資訊，請參閱 BaseValidator。
可及性
根據預設為這個控制項呈現的標記，可能與可及性標準 (例如 Web 內容可及性方針 1.0 (WCAG) 優先權 1 方針) 不一致。如需這個控制項之可及性支援的詳細資料，請參閱 ASP.NET 控制項和網頁可及性。
下列範例說明如何使用 RequiredFieldValidator 控制項來確認使用者輸入數值至文字方塊中。
.gif "安全性注意事項") 安全性注意事項： |
|---|
這個範例有一個可接受使用者輸入的文字方塊，這可能會造成安全性威脅。根據預設，ASP.NET Web 網頁會驗證使用者輸入未包含指令碼或 HTML 項目。如需詳細資訊，請參閱 指令碼攻擊概觀。 |
<%@ 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 >
<head>
<title>RequiredField Validator Example</title>
<script runat="server">
Sub ValidateBtn_Click(sender As Object, e As EventArgs)
If Page.IsValid Then
lblOutput.Text = "Required field is filled!"
Else
lblOutput.Text = "Required field is empty!"
End If
End Sub
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>RequiredField Validator Example</h3>
<table style="background-color:#eeeeee; padding:10">
<tr valign="top">
<td colspan="3">
<asp:Label ID="lblOutput"
Text="Fill in the required field below"
runat="server"
AssociatedControlID="TextBox1"/>
<br />
</td>
</tr>
<tr>
<td colspan="3">
<b>Credit Card Information</b>
</td>
</tr>
<tr>
<td align="right">
Card Number:
</td>
<td>
<asp:TextBox id="TextBox1"
runat="server"/>
</td>
<td>
<asp:RequiredFieldValidator id="RequiredFieldValidator2"
ControlToValidate="TextBox1"
Display="Static"
ErrorMessage="*"
runat="server"/>
</td>
</tr>
<tr>
<td></td>
<td>
<asp:Button id="Button1"
Text="Validate"
OnClick="ValidateBtn_Click"
runat="server"/>
</td>
<td></td>
</tr>
</table>
</form>
</body>
</html>
<%@ 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 >
<head>
<title>RequiredField Validator Example</title>
<script runat="server">
void ValidateBtn_Click(Object sender, EventArgs e)
{
if (Page.IsValid)
{
lblOutput.Text = "Required field is filled!";
}
else
{
lblOutput.Text = "Required field is empty!";
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<h3>RequiredField Validator Example</h3>
<table style="background-color:#eeeeee; padding:10">
<tr valign="top">
<td colspan="3">
<asp:Label ID="lblOutput"
Text="Fill in the required field below"
runat="server"
AssociatedControlID="TextBox1"/>
<br />
</td>
</tr>
<tr>
<td colspan="3">
<b>Credit Card Information</b>
</td>
</tr>
<tr>
<td align="right">
Card Number:
</td>
<td>
<asp:TextBox id="TextBox1"
runat="server"/>
</td>
<td>
<asp:RequiredFieldValidator id="RequiredFieldValidator2"
ControlToValidate="TextBox1"
Display="Static"
ErrorMessage="*"
runat="server"/>
</td>
</tr>
<tr>
<td></td>
<td>
<asp:Button id="Button1"
Text="Validate"
OnClick="ValidateBtn_Click"
runat="server"/>
</td>
<td></td>
</tr>
</table>
</form>
</body>
</html>
<html>
<head>
<script language="C#" runat=server>
</script>
</head>
<body>
<h3><font face="Verdana">RequiredField Validator Sample</font></h3>
<p>
<form runat="server">
<table bgcolor="#eeeeee" cellpadding=10>
<tr valign="top">
<td colspan=3>
<asp:Label ID="lblOutput"
Text="Fill in the required field below"
ForeColor="red"
Font-Name="Verdana"
Font-Size="10" runat=server /><br>
</td>
</tr>
<tr>
<td colspan=3>
<font face=Verdana size=2><b>Credit Card Information</b></font>
</td>
</tr>
<tr>
<td align=right>
<font face=Verdana size=2>Card Number:</font>
</td>
<td>
<asp:TextBox id=TextBox1 runat=server />
</td>
<td>
<asp:RequiredFieldValidator id="RequiredFieldValidator2"
ControlToValidate="TextBox1"
Display="Static"
Width="100%" runat=server>
*
</asp:RequiredFieldValidator>
</td>
</tr>
<tr>
<td></td>
<td>
<asp:Button id=Button1
text="Validate"
OnClick="ValidateBtn_Click"
runat=server />
</td>
<td></td>
</tr>
</table>
</form>
</body>
</html>
System..::.Object
System.Web.UI..::.Control
System.Web.UI.WebControls..::.WebControl
System.Web.UI.WebControls..::.Label
System.Web.UI.WebControls..::.BaseValidator
System.Web.UI.WebControls..::.RequiredFieldValidator
這個型別的任何 Public static (在 Visual Basic 中為 Shared) 成員都具備執行緒安全。並非所有的執行個體成員都是安全執行緒。
Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
.NET Framework 和 .NET Compact Framework 並不支援各種平台的所有版本。如需支援平台版本的相關資訊，請參閱 .NET Framework 系統需求。
.NET Framework
支援版本：3.5、3.0、2.0、1.1、1.0
參考