Membership.RequiresQuestionAndAnswer Propriedade

Definição

Espaço de Nomes:
System.Web.Security
Assemblagem:
System.Web.dll

Obtém um valor que indica se o fornecedor de subscrição por defeito exige que o utilizador responda a uma pergunta de palavra-passe para redefinição e recuperação da palavra-passe.

public:
 static property bool RequiresQuestionAndAnswer { bool get(); };
public static bool RequiresQuestionAndAnswer { get; }
static member RequiresQuestionAndAnswer : bool
Public Shared ReadOnly Property RequiresQuestionAndAnswer As Boolean

Valor de Propriedade

Boolean

true se for necessária uma resposta por palavra-passe para o reset e recuperação; caso contrário, false.

Exemplos

O seguinte exemplo de código mostra o elemento membership na secção system.web do ficheiro Web.config para uma aplicação ASP.NET. Especifica que a aplicação utilize uma instância do SqlMembershipProvider, permite a redefinição da palavra-passe e exige uma resposta por palavra-passe ao realizar uma redefinição.

<membership defaultProvider="SqlProvider" userIsOnlineTimeWindow="20">
  <providers>
    <add name="SqlProvider"
      type="System.Web.Security.SqlMembershipProvider"
      connectionStringName="SqlServices"
      enablePasswordRetrieval="false"
      enablePasswordReset="true"
      requiresQuestionAndAnswer="true"
      passwordFormat="Hashed"
      applicationName="MyApplication" />
  </providers>
</membership>

O exemplo de código seguinte verifica o valor de RequiresQuestionAndAnswer e adiciona os controlos necessários para que uma pergunta e resposta de palavra-passe sejam fornecidas ao criar um utilizador.

Importante

Este exemplo inclui uma caixa de texto que aceita a entrada do utilizador, o que constitui uma potencial ameaça à segurança. Por defeito, as páginas Web do ASP.NET validam que a entrada do utilizador não inclui elementos de script ou HTML. Para mais informações, consulte Visão Geral dos Exploits de Scripts.

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Web.Security" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

public void CreateUser_OnClick(object sender, EventArgs args)
{
  // Create new user and retrieve create status result.

  MembershipCreateStatus status;
  string passwordQuestion = "";
  string passwordAnswer = "";

  if (Membership.RequiresQuestionAndAnswer)
  {
    passwordQuestion = PasswordQuestionTextbox.Text;
    passwordAnswer = PasswordAnswerTextbox.Text;
  }

  try
  {
    MembershipUser newUser = Membership.CreateUser(UsernameTextbox.Text, PasswordTextbox.Text, 
                                                   EmailTextbox.Text, passwordQuestion,
                                                   passwordAnswer, true, out status);
    if (newUser == null)
    {
      Msg.Text = GetErrorMessage(status);
    }
    else
    {
      Response.Redirect("login.aspx");
    }
  }
  catch
  {
    Msg.Text = "An exception occurred creating the user.";
  }
}

public string GetErrorMessage(MembershipCreateStatus status)
{
   switch (status)
   {
      case MembershipCreateStatus.DuplicateUserName:
        return "Username already exists. Please enter a different user name.";

      case MembershipCreateStatus.DuplicateEmail:
        return "A username for that email address already exists. Please enter a different email address.";

      case MembershipCreateStatus.InvalidPassword:
        return "The password provided is invalid. Please enter a valid password value.";

      case MembershipCreateStatus.InvalidEmail:
        return "The email address provided is invalid. Please check the value and try again.";

      case MembershipCreateStatus.InvalidAnswer:
        return "The password retrieval answer provided is invalid. Please check the value and try again.";

      case MembershipCreateStatus.InvalidQuestion:
        return "The password retrieval question provided is invalid. Please check the value and try again.";

      case MembershipCreateStatus.InvalidUserName:
        return "The user name provided is invalid. Please check the value and try again.";

      case MembershipCreateStatus.ProviderError:
        return "The authentication provider returned an error. Please verify your entry and try again. If the problem persists, please contact your system administrator.";

      case MembershipCreateStatus.UserRejected:
        return "The user creation request has been canceled. Please verify your entry and try again. If the problem persists, please contact your system administrator.";

      default:
        return "An unknown error occurred. Please verify your entry and try again. If the problem persists, please contact your system administrator.";
   }
}

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Create User</title>
</head>
<body>

<form id="form1" runat="server">
  <h3>Create New User</h3>

  <asp:Label id="Msg" ForeColor="maroon" runat="server" /><br />

  <table cellpadding="3" border="0">
    <tr>
      <td>Username:</td>
      <td><asp:Textbox id="UsernameTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="UsernameRequiredValidator" runat="server"
                                      ControlToValidate="UserNameTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>
    <tr>
      <td>Password:</td>
      <td><asp:Textbox id="PasswordTextbox" runat="server" TextMode="Password" /></td>
      <td><asp:RequiredFieldValidator id="PasswordRequiredValidator" runat="server"
                                      ControlToValidate="PasswordTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>
    <tr>
      <td>Confirm Password:</td>
      <td><asp:Textbox id="PasswordConfirmTextbox" runat="server" TextMode="Password" /></td>
      <td><asp:RequiredFieldValidator id="PasswordConfirmRequiredValidator" runat="server"
                                      ControlToValidate="PasswordConfirmTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" />
          <asp:CompareValidator id="PasswordConfirmCompareValidator" runat="server"
                                      ControlToValidate="PasswordConfirmTextbox" ForeColor="red"
                                      Display="Static" ControlToCompare="PasswordTextBox"
                                      ErrorMessage="Confirm password must match password." />
      </td>
    </tr>
    <tr>
      <td>Email Address:</td>
      <td><asp:Textbox id="EmailTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="EmailRequiredValidator" runat="server"
                                      ControlToValidate="EmailTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>


<% if (Membership.RequiresQuestionAndAnswer) { %>

    <tr>
      <td>Password Question:</td>
      <td><asp:Textbox id="PasswordQuestionTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="PasswordQuestionRequiredValidator" runat="server"
                                      ControlToValidate="PasswordQuestionTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>
    <tr>
      <td>Password Answer:</td>
      <td><asp:Textbox id="PasswordAnswerTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="PasswordAnswerRequiredValidator" runat="server"
                                      ControlToValidate="PasswordAnswerTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>

<% } %>


    <tr>
      <td></td>
      <td><asp:Button id="CreateUserButton" Text="Create User" OnClick="CreateUser_OnClick" runat="server" /></td>
    </tr>
  </table>
</form>

</body>
</html>

<%@ Page Language="VB" %>
<%@ Import Namespace="System.Web.Security" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<script runat="server">

Public Sub CreateUser_OnClick(sender As Object, args As EventArgs)

  ' Create new user and retrieve create status result.

  Dim status As MembershipCreateStatus
  Dim passwordQuestion As String = ""
  Dim passwordAnswer As String = ""

  If Membership.RequiresQuestionAndAnswer Then
    passwordQuestion = PasswordQuestionTextbox.Text
    passwordAnswer = PasswordAnswerTextbox.Text
  End If

  Try
    Dim newUser As MembershipUser = Membership.CreateUser(UsernameTextbox.Text, PasswordTextbox.Text, _
                                                   EmailTextbox.Text, passwordQuestion, _
                                                   passwordAnswer, True, status)
    If newUser Is Nothing Then
      Msg.Text = GetErrorMessage(status)
    Else
       Response.Redirect("login.aspx")
    End If
  Catch
    Msg.Text = "An exception occurred creating the user."
  End Try

End Sub

Public Function GetErrorMessage(status As MembershipCreateStatus) As String

   Select Case status
   
      Case MembershipCreateStatus.DuplicateUserName:
        Return "Username already exists. Please enter a different user name."

      Case MembershipCreateStatus.DuplicateEmail:
        Return "A username for that email address already exists. Please enter a different email address."

      Case MembershipCreateStatus.InvalidPassword:
        Return "The password provided is invalid. Please enter a valid password value."

      Case MembershipCreateStatus.InvalidEmail:
        Return "The email address provided is invalid. Please check the value and try again."

      Case MembershipCreateStatus.InvalidAnswer:
        Return "The password retrieval answer provided is invalid. Please check the value and try again."

      Case MembershipCreateStatus.InvalidQuestion:
        Return "The password retrieval question provided is invalid. Please check the value and try again."

      Case MembershipCreateStatus.InvalidUserName
        Return "The user name provided is invalid. Please check the value and try again."

      Case MembershipCreateStatus.ProviderError:
        Return "The authentication provider returned an error. Please verify your entry and try again. If the problem persists, please contact your system administrator."

      Case MembershipCreateStatus.UserRejected:
        Return "The user creation request has been canceled. Please verify your entry and try again. If the problem persists, please contact your system administrator."

      Case Else:
        Return "An unknown error occurred. Please verify your entry and try again. If the problem persists, please contact your system administrator."
   End Select

End Function

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
<title>Create User</title>
</head>
<body>

<form id="form1" runat="server">
  <h3>Create New User</h3>
  <asp:Label id="Msg" ForeColor="maroon" runat="server" />
  <table cellpadding="3" border="0">
    <tr>
      <td>Username:</td>
      <td><asp:Textbox id="UsernameTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="UsernameRequiredValidator" runat="server"
                                      ControlToValidate="UserNameTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>
    <tr>
      <td>Password:</td>
      <td><asp:Textbox id="PasswordTextbox" runat="server" TextMode="Password" /></td>
      <td><asp:RequiredFieldValidator id="PasswordRequiredValidator" runat="server"
                                      ControlToValidate="PasswordTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>
    <tr>
      <td>Confirm Password:</td>
      <td><asp:Textbox id="PasswordConfirmTextbox" runat="server" TextMode="Password" /></td>
      <td><asp:RequiredFieldValidator id="PasswordConfirmRequiredValidator" runat="server"
                                      ControlToValidate="PasswordConfirmTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" />
          <asp:CompareValidator id="PasswordConfirmCompareValidator" runat="server"
                                      ControlToValidate="PasswordConfirmTextbox" ForeColor="red"
                                      Display="Static" ControlToCompare="PasswordTextBox"
                                      ErrorMessage="Confirm password must match password." />
      </td>
    </tr>
    <tr>
      <td>Email Address:</td>
      <td><asp:Textbox id="EmailTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="EmailRequiredValidator" runat="server"
                                      ControlToValidate="EmailTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>


<% If Membership.RequiresQuestionAndAnswer Then %>

    <tr>
      <td>Password Question:</td>
      <td><asp:Textbox id="PasswordQuestionTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="PasswordQuestionRequiredValidator" runat="server"
                                      ControlToValidate="PasswordQuestionTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>
    <tr>
      <td>Password Answer:</td>
      <td><asp:Textbox id="PasswordAnswerTextbox" runat="server" /></td>
      <td><asp:RequiredFieldValidator id="PasswordAnswerRequiredValidator" runat="server"
                                      ControlToValidate="PasswordAnswerTextbox" ForeColor="red"
                                      Display="Static" ErrorMessage="Required" /></td>
    </tr>

<% End If %>


    <tr>
      <td></td>
      <td><asp:Button id="CreateUserButton" Text="Create User" OnClick="CreateUser_OnClick" runat="server" /></td>
    </tr>
  </table>
</form>

</body>
</html>

Observações

Exigir uma pergunta e resposta com palavra-passe proporciona uma camada adicional de segurança ao recuperar ou redefinir a palavra-passe de um utilizador. Os utilizadores podem fornecer uma pergunta e resposta quando o seu nome de utilizador é criado, que podem usar mais tarde para recuperar ou redefinir uma palavra-passe esquecida.

RequiresQuestionAndAnswer é verificado quando ResetPassword ou GetPassword é chamado. O fornecedor fornecido com .NET Framework lança um NotSupportedException se RequiresQuestionAndAnswer for true e a resposta da palavra-passe fornecida for null.

Se EnablePasswordReset e EnablePasswordRetrieval forem ambos false, RequiresQuestionAndAnswer podem ainda ser usados para impor a criação de perguntas e respostas quando novos utilizadores forem criados; no entanto, a pergunta e resposta não serão usadas. Poderás recuperar a pergunta usando a MembershipUser aula.

Para obter mais informações, consulte ResetPassword e GetPassword.

Aplica-se a

Ver também