为什么我的wcf服务中的枚举值数组为空?

我有一个wcf请求的枚举数组,它作为 null 不管我做了什么尝试。 除了枚举问题外,该服务还可以工作。

有人知道为什么会这样吗?

枚举代码:

    [DataContract(Namespace = "http://services.myproject.com/requests/MyProject")]
    public enum Recommendation
    {
        [EnumMember]
        One = 1,
        [EnumMember]
        Two = 2,            
    }

SOAP XML:

 ... xmlns:lat="http://services.myproject.com/requests/MyProject" ...
 ...
 <lat:Recommendations>
        <Recommendation>One</Recommendation>
        <Recommendation>Two</Recommendation>
 </lat:Recommendations>
 ...

C:

[DataContract(Namespace = "http://services.myproject.com/requests/MyProject")]
public class MyRequest : Request ...
{
    //...
    [DataMember]
    public Recommendation[] Recommendations { get; set; }
    //...
}