ClientRoleProvider.IsUserInRole(String, String) 方法

定义

命名空间:

System.Web.ClientServices.Providers

程序集:

System.Web.Extensions.dll

获取一个值，该值指示指定的用户是否处于指定角色中。

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

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角色，则 true;如果指定的用户未进行身份验证或未在指定角色中，则 false。

例外

ArgumentException

username Empty 或 null。

-或-

username 不是当前经过身份验证的用户的用户名。

WebException

用户不再进行身份验证。

-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 GetRolesForUser 方法需要显式 ClientRoleProvider 引用，因此使用相同的引用来调用 IsUserInRole 方法。 如果用户处于“经理”角色，则此代码将调用未提供 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

注解

可以通过调用 staticThread.CurrentPrincipal 属性返回的 IPrincipalIsInRole 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，此属性返回 ClientRolePrincipal。 由于此类实现 IPrincipal 接口，因此无需显式引用它。 ClientRolePrincipal.IsInRole 方法在内部调用 IsUserInRole 方法。 IsUserInRole 方法使用 GetRolesForUser 方法来确定由 username 指示的用户是否在由 roleName指示的角色中。

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