何時使用 DataContract 和 DataMember 屬性？ - When to use DataContract and DataMember attributes?

問題：

I am very confused about the DataContract attribute in WCF.我對 WCF 中的DataContract屬性感到非常困惑。 As per my knowledge it is used for serializating user defined type like classes.據我所知，它用於序列化用戶定義的類型，如類。 I wrote one class which is exposed at client side like this.我寫了一個這樣在客戶端公開的類。

[DataContract]
public class Contact
{
    [DataMember]
    public int Roll { get; set; }

    [DataMember]
    public string Name { get; set; }

    [DataMember]
    public string Address { get; set; }

    [DataMember]
    public int Age { get; set; }
}

It is working properly but when I remove DataContract and DataMember it also works properly.它工作正常，但是當我刪除DataContract和DataMember它也可以正常工作。 I can't understand why it is working properly.我不明白爲什麼它可以正常工作。 Can any one tell me what is the actual use of DataContract ?誰能告訴我DataContract的實際用途是什麼？

My service contract looks like this我的服務合同看起來像這樣

[ServiceContract]    
public interface IRestServiceImpl
{
    [OperationContract]        
    Contact XmlData(string id);      
}

---

解決方案：

參考一： https://en.stackoom.com/question/KIF1
參考二： https://stackoom.com/question/KIF1