列表中派生类的XML序列化，需要在父类上设置成员

Question

作为一种业余爱好，我正在XNA和C＃中制作2D RPG。 我有一个叫做ObjectiveData的类。 它的唯一成员是一个名为ObjectiveID的字符串。 从中派生出各种其他类（GatherItemsObjectiveData，SpeakToNPCObjectiveData等）-它们都假定存储与该特定目标相关的自己的目标数据（gatherItemsObjectiveData将保存有关收集哪个项目以及多少个项目的详细信息）。 它们之间唯一的共同点是ObjectiveID，因此它为什么在父类中。

当每个派生类都有其自己的objectiveID变量时，我已经对该工作进行了XML序列化，但是我希望它位于父类中，这样我就可以在不知道它是什么派生类的情况下获得objectiveID，等等。切换到将objectID放在父对象中后，它不再起作用（例如未找到XMl元素“ objective”）。 因此，现在我试图弄清楚如何使它将ObjectiveID传递给XML文件中的其父对象。

C＃代码：

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Xml.Serialization;

    namespace RpgLibrary.QuestClasses
    {
        public class ObjectivesData
        {
            [XmlArray("ObjectivesList")]
            [XmlArrayItem("KillXObjectiveData", typeof(KillXObjectiveData))]
            [XmlArrayItem("GatherXItemsObjectiveData", typeof(GatherXItemsObjectiveData))]
            [XmlArrayItem("SpeakToNPCObjectiveData", typeof(SpeakToNPCObjectiveData))]
            [XmlArrayItem("VisitAreaObjectiveData", typeof(VisitAreaObjectiveData))]
            public List<ObjectiveData> ObjectivesList;

            public ObjectivesData()
            {
                ObjectivesList = new List<ObjectiveData>();
            }
        }

        [XmlInclude(typeof(KillXObjectiveData))]
        [XmlInclude(typeof(GatherXItemsObjectiveData))]
        [XmlInclude(typeof(SpeakToNPCObjectiveData))]
        [XmlInclude(typeof(VisitAreaObjectiveData))]
        public class ObjectiveData
        {
            public string objectiveID;

            public ObjectiveData()
            {

            }

            public ObjectiveData(string objectiveID)
            {
                this.objectiveID = objectiveID;
            }
        } 

        [XmlType(TypeName = "KillXObjectiveData")]
        public class KillXObjectiveData : ObjectiveData
        {
            public string killTotal;
            public string npcID;

            public KillXObjectiveData()
            {

            }

            public KillXObjectiveData(string killTotal, string npcID, string objectiveID)
                : base(objectiveID)
            {
                this.killTotal = killTotal;
                this.npcID = npcID;
            }
        }

        [XmlType(TypeName = "GatherXItemsObjectiveData")]
        public class GatherXItemsObjectiveData : ObjectiveData
        {
            public string gatherTotal;
            public string itemID;

            public GatherXItemsObjectiveData()
            {

            }

            public GatherXItemsObjectiveData(string gatherTotal, string itemID, string objectiveID)
                : base(objectiveID)
            {
                this.gatherTotal = gatherTotal;
                this.itemID = itemID;
            }
        }

        [XmlType(TypeName = "SpeakToNPCObjectiveData")]
        public class SpeakToNPCObjectiveData : ObjectiveData
        {
            public string npcID;

            public SpeakToNPCObjectiveData()
            {

            }

            public SpeakToNPCObjectiveData(string npcID, string objectiveID)
                : base(objectiveID)
            {
                this.npcID = npcID;
            }
        }

        [XmlType(TypeName = "VisitAreaObjectiveData")]
        public class VisitAreaObjectiveData : ObjectiveData
        {
            public string areaID;

            public VisitAreaObjectiveData()
            {

            }

            public VisitAreaObjectiveData(string areaID, string objectiveID)
                : base(objectiveID)
            {
                this.areaID = areaID;
            }
        }
    }

XML档案：

  <?xml version="1.0" encoding="utf-8"?>
  <XnaContent xmlns:QuestClasses="RpgLibrary.QuestClasses">
    <Asset Type="QuestClasses:ObjectivesData">
        <ObjectivesList>
          <Item Type="QuestClasses:GatherXItemsObjectiveData">
            <gatherTotal>5</gatherTotal>
            <itemID>1</itemID>
            <objectiveID>1</objectiveID>
          </Item>
          <Item Type="QuestClasses:KillXObjectiveData">
            <killTotal>5</killTotal>
            <npcID>900</npcID>
            <objectiveID>2</objectiveID>
          </Item>
        </ObjectivesList>
    </Asset>
  </XnaContent>

最终结果应该是，我获得了存储有所有派生类对象的ObjectiveData列表，而我只需要在父类中正确设置ObjectiveID。

Answer 1

根据您想了解的有关IntermediateSerializer ：

基类成员在派生类型的数据之前被序列化

因此，您需要将<objectiveID>元素移动到预先存在的XML文件中其包含元素的开头。