WCF中的自定义类中包括自定义枚举类型时出错

现有自定义类型EventLogItem：

public class EventLogItem
    {
        public int EventID
        {
            get;
            set;
        }
        public EventLevel EventType
        {
            get;
            set;
        }
        public string EventTime
        {
            get;
            set;
        }
        public string EventTask
        {
            get;
            set;
        }
        public string EventUser
        {
            get;
            set;
        }
        public string EventSource
        {
            get;
            set;
        }
        public string EventIP
        {
            get;
            set;
        }
        public string EventMessage
        {
            get;
            set;
        }
    }

自定义枚举类型EventLevel：

public enum EventLevel
    {
        Warning,
        Infomation
    }

WCF中定义的函数：

//sqlCore.getUserLogs()返回类型为List<EventLogItem>
[OperationContract]
        public List<EventLogItem> getLogs()
        {
            SqlCore sqlCore = new SqlCore();
            return sqlCore.getUserLogs();
        }

现在客户端调用WCF服务中的方法：

protected override void OnNavigatedTo(NavigationEventArgs e)
        {
            SeAdminSvc.SeAdminClient client = new SeAdminSvc.SeAdminClient();
            client.getLogsCompleted+=new EventHandler<SeAdminSvc.getLogsCompletedEventArgs>(client_getLogsCompleted);
            client.getLogsAsync();
        }
        private void client_getLogsCompleted(object sender, SeAdminSvc.getLogsCompletedEventArgs e)
        {
            dataGrid.ItemsSource = null;
            dataGrid.AutoGenerateColumns = true;
            dataGrid.ItemsSource = e.Result;
        }

编译后运行程序，将会收到一个异常：  “e.Result”引发了“System.Reflection.TargetInvocationException”类型的异常

其实这就是由于自定义枚举类型导致的，如果将自定义枚举类型换成String类型，问题便可迎刃而解。