Question

在开发一个用于理解序列化的测试用例的同时，我遇到了一个看起来像是一个直截了当的问题，但我无法弄明白。我希望能够将多个对象添加到列表＆lt;＆gt;然后序列化该列表（在这种情况下，我正在使用DataContractJsonSerializer）。创建对象（node1和node2）后，我想将它们添加到List＆lt;＆gt; （cn）并序列化它。但是，在添加node1和node2时，我得到一个无效的参数错误（“无法从'JSON_test.Aspirate'转换为'JSON_test.CompositeNode'）。我相信这是让阵列知道基类型的问题，但我不知道我不知道该怎么做，或者事实上这是问题（对所有这些来说还是很新的）。

谢谢。

namespace JSON_test
{
    class Program
    {
        static void Main(string[] args)
        {
            Aspirate node1 = new Aspirate(25,40);
            Dispense node2 = new Dispense(32,50);
            ObjectToSerialize cn = new ObjectToSerialize();
            cn.CompositeNode.Add (node1);
            cn.CompositeNode.Add (node2);

            MemoryStream stream1 = new MemoryStream();
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(ObjectToSerialize));
            ser.WriteObject(stream1, cn.CompositeNode);
            stream1.Position = 0;
            StreamReader sr = new StreamReader(stream1);
            Console.WriteLine(sr.ReadToEnd());
            Console.ReadLine();
        }
    }

    [DataContract]
    public class ObjectToSerialize
    {
        private List<CompositeNode> compNode;
        [DataMember]
        public List<CompositeNode> CompositeNode
        {
            get {return this.CompositeNode;}
            set { this.compNode = value; }
        }

        public ObjectToSerialize()
        { 
        }
    }

    [DataContract]
    public class CompositeNode
    {

    }

    [DataContract]
    public class Aspirate
    {
        [DataMember]
        public string NodeName = "Aspirate";
        [DataMember]
        public double ZTravelHt;
        [DataMember]
        public double IndexHt;

        public Aspirate(double ZTravelHt, double IndexHt)
        {
            this.ZTravelHt = ZTravelHt;
            this.IndexHt = IndexHt;
        }
    }

    [DataContract]
    public class Dispense 
    {
        [DataMember]
        public string NodeName = "Dispense";
        [DataMember]
        public double ZTravelHt;
        [DataMember]
        public double IndexHt;

        public Dispense(double ZTravelHt, double IndexHt)
        {
            this.ZTravelHt = ZTravelHt;
            this.IndexHt = IndexHt;            
        }
    }
}

更新

namespace JSON_test
{
    class Program
    {
        static void Main(string[] args)
        {
            Aspirate node1 = new Aspirate(25,40);
            Dispense node2 = new Dispense(32,50);
            ObjectToSerialize cn = new ObjectToSerialize();
            cn.CompositeNode.Add (node1);
            cn.CompositeNode.Add (node2);

            MemoryStream stream1 = new MemoryStream();
            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(ObjectToSerialize),
                new Type[] {typeof (Aspirate), typeof (Dispense)});
            ser.WriteObject(stream1, cn.CompositeNode);
            stream1.Position = 0;
            StreamReader sr = new StreamReader(stream1);
            Console.WriteLine(sr.ReadToEnd());
            Console.ReadLine();
        }
    }

    [DataContract]
    [KnownType(typeof(Aspirate))]
    [KnownType(typeof(Dispense))]
    public class ObjectToSerialize
    {
        private List<CompositeNode> compNode = new List<CompositeNode>();

        [DataMember]
        public List<CompositeNode> CompositeNode 
        {
            get {return this.compNode;}
            set { this.compNode = value; }
        }

        public ObjectToSerialize()
        { 

        }
    }

    [DataContract]
    [KnownType(typeof(Aspirate))]
    [KnownType(typeof(Dispense))]
    public class CompositeNode
    {

    }

    [DataContract]
    public class Aspirate : CompositeNode
    {
        [DataMember]
        public string NodeName = "Aspirate";
        [DataMember]
        public double ZTravelHt;
        [DataMember]
        public double IndexHt;

        public Aspirate(double ZTravelHt, double IndexHt)
        {
            this.ZTravelHt = ZTravelHt;
            this.IndexHt = IndexHt;
        }
    }

    [DataContract]
    public class Dispense : CompositeNode
    {
        [DataMember]
        public string NodeName = "Dispense";
        [DataMember]
        public double ZTravelHt;
        [DataMember]
        public double IndexHt;

        public Dispense(double ZTravelHt, double IndexHt)
        {
            this.ZTravelHt = ZTravelHt;
            this.IndexHt = IndexHt;            
        }
    }
}

Answer 1

您可以向KnownTypeAttribute添加ObjectToSerialize，让序列化程序知道预期的类型：

[DataContract]
[KnownType(typeof(Aspirate))]
[KnownType(typeof(Dispense))]
public class ObjectToSerialize
{
     ....
}

我了解课程Aspirate和Dispense来自CompositeNode？您的代码示例中不清楚这一点。

顺便说一下，您的代码中有错误：

get {return this.CompositeNode;}

应该是：

get {return this.compNode;}

更新：在评论中对你的问题进行了再次访问：你必须在ObjectToSerialize的构造函数中初始化集合：

public ObjectToSerialize()
{
    this.compNode = new List<CompositeNode>();
}

更新2：错误的行是：

ser.WriteObject(stream1, cn.CompositeNode);

这应该是：

ser.WriteObject(stream1, cn);

顺便说一下，你可以写下这个：

DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(ObjectToSerialize));

您已使用属性定义了已知类型。将已知类型添加到构造函数是多余的。

DataContract List＆lt;＆gt;的序列化包含对象

1 个答案: