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ClientRoleProvider.IsUserInRole(String, String) 方法

定義

取得值,指出指定的使用者是否在指定的角色中。

public:
 override bool IsUserInRole(System::String ^ username, System::String ^ roleName);
public override bool IsUserInRole (string username, string roleName);
override this.IsUserInRole : string * string -> bool
Public Overrides Function IsUserInRole (username As String, roleName As String) As Boolean

參數

username
String

用戶的名稱。

roleName
String

角色的名稱。

傳回

如果指定的用戶位於指定的角色,true;如果指定的使用者未通過驗證或不在指定的角色中,則 false

例外狀況

usernameEmptynull

-或-

username 不是目前已驗證用戶的用戶名稱。

使用者不再通過驗證。

-或-

無法使用角色服務。

範例

下列範例程式代碼示範如何直接存取此方法,以判斷使用者是否處於特定角色。 此程式代碼會先測試使用者登入是否已過期。 呼叫 GetRolesForUser 方法需要明確的 ClientRoleProvider 參考,因此使用相同的參考來呼叫 IsUserInRole 方法。 如果用戶位於「管理員」角色中,則此程式代碼會呼叫未提供 PerformManagerTask 方法。

private void AttemptManagerTask()
{
    System.Security.Principal.IIdentity identity =
        System.Threading.Thread.CurrentPrincipal.Identity;

    // Return if the authentication type is not "ClientForms". 
    // This indicates that the user is logged out.
    if (!identity.AuthenticationType.Equals("ClientForms")) return;

    try
    {
        ClientRoleProvider provider =
            (ClientRoleProvider)System.Web.Security.Roles.Provider;
        String userName = identity.Name;

        // Determine whether the user login has expired by attempting
        // to retrieve roles from the service. Call the ResetCache method
        // to ensure that the roles are retrieved from the service. If no 
        // roles are returned, then the login has expired. This assumes 
        // that every valid user has been assigned to one or more roles.
        provider.ResetCache();
        String[] roles = provider.GetRolesForUser(userName);
        if (roles.Length == 0)
        {
            MessageBox.Show(
                "Your login has expired. Please log in again to access " +
                "the roles service.", "Attempting to access user roles...");

            // Call ValidateUser with empty strings in order to 
            // display the login dialog box configured as a 
            // credentials provider.
            if (!System.Web.Security.Membership.ValidateUser(
                String.Empty, String.Empty))
            {
                MessageBox.Show("Unable to authenticate. " +
                    "Cannot retrieve user roles.", "Not logged in",
                    MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
        }

        if (provider.IsUserInRole(userName, "manager"))
        {
            PerformManagerTask();
        }
    }
    catch (System.Net.WebException)
    {
        MessageBox.Show(
            "Unable to access the remote service. " +
            "Cannot retrieve user roles.", "Warning",
            MessageBoxButtons.OK, MessageBoxIcon.Warning);
    }
}
Private Sub AttemptManagerTask()

    Dim identity As System.Security.Principal.IIdentity = _
        System.Threading.Thread.CurrentPrincipal.Identity

    ' Return if the authentication type is not "ClientForms". 
    ' This indicates that the user is logged out.
    If Not identity.AuthenticationType.Equals("ClientForms") Then Return

    Try

        Dim provider As ClientRoleProvider = _
            CType(System.Web.Security.Roles.Provider, ClientRoleProvider)
        Dim userName As String = identity.Name

        ' Determine whether the user login has expired by attempting
        ' to retrieve roles from the service. Call the ResetCache method
        ' to ensure that the roles are retrieved from the service. If no 
        ' roles are returned, then the login has expired. This assumes 
        ' that every valid user has been assigned to one or more roles.
        provider.ResetCache()
        Dim roles As String() = provider.GetRolesForUser(userName)
        If roles.Length = 0 Then

            MessageBox.Show( _
                "Your login has expired. Please log in again to access " & _
                "the roles service.", "Attempting to access user roles...")

            ' Call ValidateUser with empty strings in order to 
            ' display the login dialog box configured as a 
            ' credentials provider.
            If Not System.Web.Security.Membership.ValidateUser( _
                String.Empty, String.Empty) Then

                MessageBox.Show("Unable to authenticate. " & _
                    "Cannot retrieve user roles.", "Not logged in", _
                    MessageBoxButtons.OK, MessageBoxIcon.Error)
                Return

            End If

        End If

        If provider.IsUserInRole(userName, "manager") Then
            PerformManagerTask()
        End If

    Catch ex As System.Net.WebException

        MessageBox.Show( _
            "Unable to access the remote service. " & _
            "Cannot retrieve user roles.", "Warning", _
            MessageBoxButtons.OK, MessageBoxIcon.Warning)

    End Try

End Sub

備註

您可以藉由呼叫 staticThread.CurrentPrincipal 屬性所傳回之 IPrincipalIsInRole 方法,判斷已驗證的使用者是否處於特定角色。 針對設定為使用用戶端應用程式服務的應用程式,此屬性會傳回 ClientRolePrincipal。 因為這個類別會實作 IPrincipal 介面,所以您不需要明確地參考它。 ClientRolePrincipal.IsInRole 方法會在內部呼叫 IsUserInRole 方法。 IsUserInRole 方法會使用 GetRolesForUser 方法來判斷 username 所指示的使用者是否在 roleName所指示的角色中。

服務提供者會快取本機文件系統的角色資訊,以避免不必要的服務呼叫。 如需詳細資訊,請參閱 ClientRoleProvider 類別概觀。

適用於

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