WCF学习笔记-DataContract等价性

WCF的客户端和服务端之所以能顺利的传输某一类型的数据，其实不在于接收方的接收类型和发送方的发送类型一致，而实际是两个类型所代表的DataContract是等价的。

所谓等价性是说DataContract的命名空间和名称，及其数据字段的名称，类别也是一致的。

通常DataContract的等价性是通过DataContractAttriubte和DataMemberAttribute的Name属性来定义的，默认情况下Name属性的值就是类（结构体）的名字和属性的名字。因此如下定义效果是一样的：

[c#] [DataContract]
class Contact { ... }

[DataContract(Name = "Contact")]
class Contact { ... }

[DataContract]
class Contact { ... }

[DataContract(Name = "Contact")]
class Contact { ... }同样的，如下字段的定义效果也是一样的：

[c#] view plaincopyprint?[DataMember]
public string Name;

[DataMember(Name = "Name")]
public string Name;

[DataMember]
public string Name;

[DataMember(Name = "Name")]
public string Name;因此，通过DataContractAttribute和DataMemberAttribute的Name字段可以实现不同的数据类型可以表示等价的DataContract，如：

[c#] [DataContract]
class Contact
{
    [DataMember]
    public string FirstName;

    [DataMember]
    public string LastName;
}

[DataContract(Name = "Contact")]
class Person
{
    [DataMember(Name = "FirstName")]
    public string Name;

    [DataMember(Name = "LastName")]
    public string Surname;
}

[DataContract]
class Contact
{
    [DataMember]
    public string FirstName;

    [DataMember]
    public string LastName;
}

[DataContract(Name = "Contact")]
class Person
{
    [DataMember(Name = "FirstName")]
    public string Name;

    [DataMember(Name = "LastName")]
    public string Surname;
}但是DataMemberAttribute还有一个属性是Order，如下定义的两个类则不是等价的。

[c#] [DataContract]
class Contact
{
    [DataMember]
    public string FirstName;

    [DataMember]
    public string LastName;
}

[DataContract(Name = "Contact")]
class Person
{
    [DataMember(Name = "FirstName", Order = 2)]
    public string Name;

    [DataMember(Name = "LastName", Order = 1)]
    public string Surname;
}

[DataContract]
class Contact
{
    [DataMember]
    public string FirstName;

    [DataMember]
    public string LastName;
}

[DataContract(Name = "Contact")]
class Person
{
    [DataMember(Name = "FirstName", Order = 2)]
    public string Name;

    [DataMember(Name = "LastName", Order = 1)]
    public string Surname;
}Order属性决定了DataContract序列化和反序列化的顺序，默认情况下，序列化和反序列化都是自上往下的，如果有继承关系，也是按先基类后子类的顺序。但是有一点需要注意就是，如果使用DataMember的Name属性重新命名DataContract的字段时，可能会打乱默认的序列化顺序。如下定义也不是等价的：

[c#] [DataContract]
class Contact
{
    [DataMember]
    public string FirstName;

    [DataMember]
    public string LastName;

    [DataMember]
    public int Age;
}

[DataContract(Name = "Contact")]
class Person
{
    [DataMember(Name = "FirstName")]
    public string Name;

    [DataMember(Name = "LastName")]
    public string Surname;

    [DataMember]
    public int Age;
}

[DataContract]
class Contact
{
    [DataMember]
    public string FirstName;

    [DataMember]
    public string LastName;

    [DataMember]
    public int Age;
}

[DataContract(Name = "Contact")]
class Person
{
    [DataMember(Name = "FirstName")]
    public string Name;

    [DataMember(Name = "LastName")]
    public string Surname;

    [DataMember]
    public int Age;
}Person类的序列化顺序其实是Age, FirstName, LastName，因此需要显示的添加Order属性，如果类中的Order属性是相等的，那么就会按照自顶向下的顺序序列化和反序列化。

补充：软件开发 , C# ,