ClientRoleProvider.IsUserInRole(String, String) 方法

定义

命名空间:

System.Web.ClientServices.Providers

程序集:

System.Web.Extensions.dll

获取一个指示指定用户是否属于指定角色的值。

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

参数

username

String

用户的名称。

roleName

String

角色的名称。

返回

Boolean

如果指定用户处于指定的角色，则为 true；如果指定用户未通过身份验证或者不处于指定的角色，则为 false。

例外

ArgumentException

username 是 Empty 或 null。

- 或 -

username 不是当前通过身份验证的用户的用户名。

WebException

用户不再是通过身份验证的用户。

- 或 -

角色服务不可用。

示例

以下示例代码演示如何直接访问此方法，以确定用户是否处于特定角色。 此代码首先测试用户登录名是否已过期。 调用 方法需要GetRolesForUser显式ClientRoleProvider引用，因此使用相同的引用来调用 IsUserInRole 方法。 如果用户是“经理”角色，则此代码会调用 PerformManagerTask 未提供的方法。

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

注解

可以通过调用 IsInRole 属性返回staticThread.CurrentPrincipal的 的 IPrincipal 方法来确定经过身份验证的用户是否处于特定角色。 对于配置为使用客户端应用程序服务的应用程序，此属性会返回 ClientRolePrincipal。 因为此类实现 IPrincipal 接口，所以无需显式引用它。 方法 ClientRolePrincipal.IsInRole 在内部调用 IsUserInRole 方法。 方法 IsUserInRole 使用 GetRolesForUser 方法确定 所 username 指示的用户是否为 所 roleName指示的角色。

服务提供商缓存有关本地文件系统的角色信息，以避免不必要的服务调用。 有关详细信息，请参阅 ClientRoleProvider 类概述。

另请参阅

• GetRolesForUser(String)
• CurrentPrincipal
• ClientRolePrincipal
• IsInRole(String)
• 客户端应用程序服务