Login.OnLoggingIn(LoginCancelEventArgs) 方法

參考

定義

命名空間:: System.Web.UI.WebControls

組件:: System.Web.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

在使用者送出登入資訊之後，但在進行驗證之前，會引發 LoggingIn 事件。

protected:
 virtual void OnLoggingIn(System::Web::UI::WebControls::LoginCancelEventArgs ^ e);

protected virtual void OnLoggingIn (System.Web.UI.WebControls.LoginCancelEventArgs e);

abstract member OnLoggingIn : System.Web.UI.WebControls.LoginCancelEventArgs -> unit
override this.OnLoggingIn : System.Web.UI.WebControls.LoginCancelEventArgs -> unit

Protected Overridable Sub OnLoggingIn (e As LoginCancelEventArgs)

參數

e: LoginCancelEventArgs

包含事件資料的 LoginCancelEventArgs。

範例

下列程式碼範例會 LoggingIn 使用事件來確保使用者已在屬性中 UserName 輸入格式正確的電子郵件地址。如果沒有， LoggingIn 事件處理常式會取消登入嘗試，並顯示屬性中指定的 InstructionText 錯誤訊息。

<%@ page language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
// This custom Login control checks the user name 
// entered by the user is a valid email address
class CustomLogin : Login
{
    bool IsValidEmail(string strIn)
    {
        // Return true if strIn is in valid email format.
        return Regex.IsMatch(strIn, @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$"); 
    }

    override protected void OnLoggingIn(System.Web.UI.WebControls.LoginCancelEventArgs e)
    {
        if (!IsValidEmail(UserName)) 
        {
            InstructionText = "You must enter a valid email address.";
            e.Cancel = true;
        }
        else 
        {
            InstructionText = String.Empty;
        }
    }
}

    // Add the custom login control to the page.
    void Page_Load(object sender, EventArgs e) 
    {
        CustomLogin loginControl = new CustomLogin();
        loginControl.ID = "loginControl";
        Placeholder1.Controls.Add(loginControl);
    }

</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
    <head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
        <form id="Form1" runat="server">
            <asp:placeholder id="Placeholder1" runat="server"></asp:placeholder>
        </form>
    </body>
</html>

<%@ page language="VB" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">
    ' This custom Login control checks the user name
    ' entered by the user is a valid email address.
    Class CustomLogin
        Inherits Login
        
        Function IsValidEmail(ByVal strIn As String) As Boolean
            ' Return true if strIn is in valid email format.
            Return Regex.IsMatch(strIn, ("^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$"))
        End Function

        Overrides Protected Sub OnLoggingIn(ByVal e As System.Web.UI.WebControls.LoginCancelEventArgs)
            If Not IsValidEmail(UserName) Then
                InstructionText = "You must enter a valid email address."
                e.Cancel = True
            Else
                InstructionText = String.Empty
            End If
        End Sub
    End Class
    
    ' Add the custom login control to the page.
    Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
        Dim loginControl As New CustomLogin

        loginControl.ID = "loginControl"

        PlaceHolder1.Controls.Add(loginControl)
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>ASP.NET Example</title>
</head>
<body>
<form id="Form1" runat="server">
    <asp:placeholder id="Placeholder1" runat="Server"></asp:placeholder>
</form>
</body>
</html>

下列程式碼範例示範如何擴充 Login 控制項。控制項 CustomLogin 包含一個 DropDownList 控制項，可讓使用者選擇他們用來驗證的成員資格提供者。 (這些提供者是在 Web.config.) 在方法中 OnLoggingIn 設定，屬性 MembershipProvider 會設定為控制項的 DropDownList 選取值。

重要

此範例包含接受使用者輸入的文字方塊，這是潛在的安全性威脅。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 Script Exploits Overview (指令碼攻擊概觀)。

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

namespace Samples.AspNet.Controls
{
    public sealed class CustomLogin : Login
    {
        public CustomLogin() { }
        
        protected override void OnLoggingIn(LoginCancelEventArgs e)
        {
            // Set the Membership provider for the Login control from a DropDownList.
            DropDownList list = (DropDownList)this.FindControl("domain");
            this.MembershipProvider = list.SelectedValue;
            base.OnLoggingIn(e);
        }
        
        protected override void CreateChildControls()
        {
            LayoutTemplate = new MyTemplate();
            base.CreateChildControls();
        }
    }
    
    // A Template that contains the child controls.
    public class MyTemplate : ITemplate
    {
        void ITemplate.InstantiateIn(Control container)
        {
            // A TextBox for the user name.
            TextBox username = new TextBox();
            username.ID = "username";
            
            // A TextBox for the password.
            TextBox password = new TextBox();
            password.ID = "password";
            
            // A CheckBox to remember the user on subsequent visits.
            CheckBox remember = new CheckBox();
            remember.ID = "RememberMe";
            remember.Text = "Don't forget me!";
            
            // Failure Text.
            Literal failure = new Literal();
            failure.ID = "FailureText";
            
            // A DropDownList to choose the Membership provider.
            DropDownList domain = new DropDownList();
            domain.ID = "Domain";
            domain.Items.Add(new ListItem("SqlMembers"));
            domain.Items.Add(new ListItem("SqlMembers2"));
            
            // A Button to log in.
            Button submit = new Button();
            submit.CommandName = "login";
            submit.Text = "LOGIN";

            container.Controls.Add(new LiteralControl("UserName:"));
            container.Controls.Add(username);
            container.Controls.Add(new LiteralControl("<br>Password:"));
            container.Controls.Add(password);
            container.Controls.Add(new LiteralControl("<br>"));
            container.Controls.Add(remember);
            container.Controls.Add(new LiteralControl("<br>Domain:"));
            container.Controls.Add(domain);
            container.Controls.Add(new LiteralControl("<br>"));
            container.Controls.Add(failure);
            container.Controls.Add(new LiteralControl("<br>"));
            container.Controls.Add(submit);
        }
    }    
}

Imports System.Data
Imports System.Configuration
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls

Namespace Samples.AspNet.Controls

    NotInheritable Public Class CustomLogin
        Inherits Login

        Public Sub New() 
        End Sub

        Protected Overrides Sub OnLoggingIn(ByVal e As LoginCancelEventArgs) 

            ' Set the Membership provider for the Login control from a DropDownList.
            Dim list As DropDownList = CType(Me.FindControl("domain"), DropDownList)
            Me.MembershipProvider = list.SelectedValue
            MyBase.OnLoggingIn(e)

        End Sub


        Protected Overrides Sub CreateChildControls() 

            LayoutTemplate = New MyTemplate()
            MyBase.CreateChildControls()

        End Sub
    End Class

    ' A Template that contains the child controls.
    Public Class MyTemplate
        Implements ITemplate

        Sub InstantiateIn(ByVal container As Control)  Implements ITemplate.InstantiateIn
            ' A TextBox for the user name.
            Dim username As New TextBox()
            username.ID = "username"

            ' A TextBox for the password.
            Dim password As New TextBox()
            password.ID = "password"

            ' A CheckBox to remember the user on subsequent visits.
            Dim remember As New CheckBox()
            remember.ID = "RememberMe"
            remember.Text = "Don't forget me!"

            ' Failure Text.
            Dim failure As New Literal()
            failure.ID = "FailureText"

            ' A DropDownList to choose the Membership provider.
            Dim domain As New DropDownList()
            domain.ID = "Domain"
            domain.Items.Add(New ListItem("SqlMembers"))
            domain.Items.Add(New ListItem("SqlMembers2"))

            ' A Button to log in.
            Dim submit As New Button()
            submit.CommandName = "login"
            submit.Text = "LOGIN"

            container.Controls.Add(New LiteralControl("UserName:"))
            container.Controls.Add(username)
            container.Controls.Add(New LiteralControl("<br>Password:"))
            container.Controls.Add(password)
            container.Controls.Add(New LiteralControl("<br>"))
            container.Controls.Add(remember)
            container.Controls.Add(New LiteralControl("<br>Domain:"))
            container.Controls.Add(domain)
            container.Controls.Add(New LiteralControl("<br>"))
            container.Controls.Add(failure)
            container.Controls.Add(New LiteralControl("<br>"))
            container.Controls.Add(submit)

        End Sub
    End Class
End Namespace

備註

OnLoggingIn 方法會引發 LoggingIn 事件。使用 LoggingIn 事件來執行驗證使用者之前所需的任何處理，或執行自訂驗證。

引發事件會透過委派叫用此事件處理常式。如需詳細資訊，請參閱處理和引發事件。

OnLoggingIn 方法也允許衍生類別處理事件，而不用附加委派。這是在衍生類別中處理事件的慣用技巧。

給繼承者的注意事項

當在衍生類別中覆寫 OnLoggingIn(LoginCancelEventArgs) 時，請確定呼叫基底類別的 OnLoggingIn(LoginCancelEventArgs) 方法，使已註冊的委派能接收到事件。

適用於

另請參閱

ASP.NET 登入控制項概觀

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Login.OnLoggingIn(LoginCancelEventArgs) 方法

定義

參數

範例

備註

給繼承者的注意事項

適用於

另請參閱

意見反應

其他資源