Question

我使用this blog entry中定义的SerializableDictionary来存储<string, object>数据，并将其传递给WCF服务或从WCF服务传递。如果我使用值类型作为值，这可以正常工作，因为它们可以很容易地装箱成为object。但是，如果我使用像

这样的东西

new List<int>() { 5, 10 }，我得到一个例外：

类型System.Collections.Generic.List`1 [[System.Int32，mscorlib，Version = 4.0.0.0，Culture = neutral，PublicKeyToken = b77a5c561934e089]]可能不会在此上下文中使用。

根据讨论here，我应该使用value.GetType()初始化XmlSerializer;然而，虽然这让我序列化，但我不知道如何以一般方式反序列化回SerializableDictionary。

我不确定是否有办法彻底改变它，同时仍允许<string, object>作为我的类型参数 - 我可以将值序列化为二进制而不是XML并以这种方式传输（相同的代码是序列化和反序列化，所以我不关心互操作性），但我想尽可能使用XML。

修改

完整代码示例：

XmlSerializer serializer = new XmlSerializer(typeof(SerializableDictionary<string, object>));
SerializableDictionary<string, object> dic = new SerializableDictionary<string, object>();
dic["test"] = new List<int>() { 5, 10 };
StringBuilder sb = new StringBuilder();
XmlWriter writer = XmlWriter.Create(sb);
serializer.Serialize(writer, dic);
string ser = sb.ToString();

解

感谢 Nico Schertler 为我提供了正确的答案。我在这里发布我的最终代码，万一有人需要它。这与第一个链接中的原始代码向后兼容，因此该代码序列化的任何内容都可以通过以下方式反序列化。

[XmlRoot("dictionary")]
public class SerializableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, IXmlSerializable
{

    #region " IXmlSerializable Members "

    #region " WriteXml "

    public void WriteXml(XmlWriter writer)
    {
        // Base types
        string baseKeyType = typeof(TKey).AssemblyQualifiedName;
        string baseValueType = typeof(TValue).AssemblyQualifiedName;
        writer.WriteAttributeString("keyType", baseKeyType);
        writer.WriteAttributeString("valueType", baseValueType);

        foreach (TKey key in this.Keys)
        {
            // Start
            writer.WriteStartElement("item");

            // Key
            Type keyType = key.GetType();
            XmlSerializer keySerializer = GetTypeSerializer(keyType.AssemblyQualifiedName);

            writer.WriteStartElement("key");
            if (keyType != typeof(TKey)) { writer.WriteAttributeString("type", keyType.AssemblyQualifiedName); }
            keySerializer.Serialize(writer, key);
            writer.WriteEndElement();

            // Value
            TValue value = this[key];
            Type valueType = value.GetType();
            XmlSerializer valueSerializer = GetTypeSerializer(valueType.AssemblyQualifiedName);

            writer.WriteStartElement("value");
            if (valueType != typeof(TValue)) { writer.WriteAttributeString("type", valueType.AssemblyQualifiedName); }
            valueSerializer.Serialize(writer, value);
            writer.WriteEndElement();

            // End
            writer.WriteEndElement();
        }
    }

    #endregion

    #region " ReadXml "

    public void ReadXml(XmlReader reader)
    {
        bool wasEmpty = reader.IsEmptyElement;
        reader.Read();

        if (wasEmpty)
        {
            return;
        }

        // Base types
        string baseKeyType = typeof(TKey).AssemblyQualifiedName;
        string baseValueType = typeof(TValue).AssemblyQualifiedName;

        while (reader.NodeType != XmlNodeType.EndElement)
        {
            // Start
            reader.ReadStartElement("item");

            // Key
            XmlSerializer keySerializer = GetTypeSerializer(reader["type"] ?? baseKeyType);
            reader.ReadStartElement("key");
            TKey key = (TKey)keySerializer.Deserialize(reader);
            reader.ReadEndElement();

            // Value
            XmlSerializer valueSerializer = GetTypeSerializer(reader["type"] ?? baseValueType);
            reader.ReadStartElement("value");
            TValue value = (TValue)valueSerializer.Deserialize(reader);
            reader.ReadEndElement();

            // Store
            this.Add(key, value);

            // End
            reader.ReadEndElement();
            reader.MoveToContent();
        }
        reader.ReadEndElement();
    }

    #endregion

    #region " GetSchema "

    public XmlSchema GetSchema()
    {
        return null;
    }

    #endregion

    #endregion

    #region " GetTypeSerializer "

    private static readonly Dictionary<string, XmlSerializer> _serializers = new Dictionary<string, XmlSerializer>();
    private static readonly object _deadbolt = new object();
    private XmlSerializer GetTypeSerializer(string type)
    {
        if (!_serializers.ContainsKey(type))
        {
            lock (_deadbolt)
            {
                if (!_serializers.ContainsKey(type))
                {
                    _serializers.Add(type, new XmlSerializer(Type.GetType(type)));
                }
            }
        }
        return _serializers[type];
    }

    #endregion

}

我只是写出类型，如果它与基类型不同，以便保持XML的长度，我保留一个XmlSerializer的静态列表，以防止对它们进行实例化到处都是。我必须在开头写出提供的类型，以便能够防止在每个节点上写出类型。

Answer 1

序列化的问题是（解）序列化程序需要知道如何处理对象。 object的序列化程序不知道如何序列化List<int>。

对于序列化，您已经在问题中给出了答案。使用value.GetType()确定值的类型。此外，您必须保存类型本身。使用类型（type.AssemblyQualifiedName）的字符串表示可以轻松实现这一点。

TValue value = this[key];

var type = value.GetType();
XmlSerializer valueSerializer = new XmlSerializer(type);

writer.WriteStartElement("type");
writer.WriteString(type.AssemblyQualifiedName); 
//you can use FullName if you don't need to address external libraries
writer.WriteEndElement();

writer.WriteStartElement("content");
valueSerializer.Serialize(writer, value);
writer.WriteEndElement();

对于反序列化，您需要读取类型并反序列化值：

reader.ReadStartElement("value");

reader.ReadStartElement("type");
var typename = reader.ReadContentAsString();
reader.ReadEndElement();
var type = Type.GetType(typename);
XmlSerializer valueSerializer = new XmlSerializer(type);

reader.ReadStartElement("content");
TValue value = (TValue)valueSerializer.Deserialize(reader);
reader.ReadEndElement();

reader.ReadEndElement();

Answer 2

在您在链接中引用的类中执行以下操作

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

namespace sampleLogin
{

    [XmlRoot("dictionary")]
    public class SerializableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, IXmlSerializable
    {
        #region IXmlSerializable Members

        public System.Xml.Schema.XmlSchema GetSchema()
        {
            return null;
        }

        public void ReadXml(System.Xml.XmlReader reader)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));
            bool wasEmpty = reader.IsEmptyElement;

            reader.Read();
            if (wasEmpty)
            {
                return;
            }

            while (reader.NodeType != System.Xml.XmlNodeType.EndElement)
            {
                reader.ReadStartElement("item");
                reader.ReadStartElement("key");
                TKey key = (TKey)keySerializer.Deserialize(reader);
                reader.ReadEndElement();
                reader.ReadStartElement("value");
                TValue value = (TValue)valueSerializer.Deserialize(reader);
                reader.ReadEndElement();
                this.Add(key, value);
                reader.ReadEndElement();
                reader.MoveToContent();
            }
            reader.ReadEndElement();
        }



        public void WriteXml(System.Xml.XmlWriter writer)
        {
            XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
            XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));

            foreach (TKey key in this.Keys)
            {
                writer.WriteStartElement("item");
                writer.WriteStartElement("key");
                keySerializer.Serialize(writer, key);
                writer.WriteEndElement();
                writer.WriteStartElement("value");
                TValue value = this[key];
                var type = value.GetType();//new line added here
                valueSerializer = new XmlSerializer(type);//New line added here 
                valueSerializer.Serialize(writer, value);
                writer.WriteEndElement();
                writer.WriteEndElement();
            }
        }
        #endregion
    }

使用对象序列化程序序列化列表

2 个答案: