Public Class RequiredFieldValidator Inherits BaseValidator
Dim instance As RequiredFieldValidator
public class RequiredFieldValidator : BaseValidator
public ref class RequiredFieldValidator : public BaseValidator
public class RequiredFieldValidator extends BaseValidator
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。
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。
<%@ Page Language="VB" AutoEventWireup="True" %> <html> <head> <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 runat="server"> <h3>RequiredField Validator Example</h3> <table bgcolor="#eeeeee" cellpadding="10"> <tr valign="top"> <td colspan="3"> <asp:Label ID="lblOutput" Text="Fill in the required field below" runat="server"/> <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" %> <html> <head> <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 runat="server"> <h3>RequiredField Validator Example</h3> <table bgcolor="#eeeeee" cellpadding="10"> <tr valign="top"> <td colspan="3"> <asp:Label ID="lblOutput" Text="Fill in the required field below" runat="server"/> <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>
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
.NET 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，請參閱系統需求一節的內容。