Data Member Order

https://docs.microsoft.com/en-us/dotnet/framework/wcf/feature-details/data-member-order

In some applications, it is useful to know the order in which data from the various data members is sent or is expected to be received (such as the order in which data appears in the serialized XML).

Sometimes it may be necessary to change this order.

This topic explains the ordering rules.

Basic Rules

The basic rules for data ordering include:

• If a data contract type is a part of an inheritance hierarchy, data members of its base types are always first in the order.

• Next in order are the current type’s data members that do not have the Order property of the DataMemberAttribute attribute set, in alphabetical order.

• Next are any data members that have the Order property of the DataMemberAttribute attribute set. These are ordered by the value of the Order property first and then alphabetically if there is more than one member of a certain Order value. Order values may be skipped.

Alphabetical order is established by calling the CompareOrdinal method.

用途

1.序列化的时候，指定顺序，和xml匹配

2.序列化的时候，属性之间有依赖关系，比如A属性在set的时候，有自己的logic，去设置了B属性。

这种情况下，必须先序列化A属性，再序列化B属性。

when a property has a logic for set or get,then apply data member attribute to field