我正在寻找可以包含在Web服务中的键/值对对象。

我尝试使用.NET的System.Collections.Generic.KeyValuePair <>类，但是它无法在Web服务中正确序列化。在Web服务中，键和值属性不会被序列化，从而使该类无用，除非有人知道解决该问题的方法。

还有其他通用类可以用于这种情况吗？

我会使用.NET的System.Web.UI.Pair类，但是它使用Object作为其类型。如果仅出于类型安全性考虑，使用Generic类会很好。

解决方案

回答

只需定义一个结构/类。

[Serializable]
public struct KeyValuePair<K,V>
{
  public K Key {get;set;}
  public V Value {get;set;}
}

回答

我不认为是因为Dictionary <>本身不是XML可序列化的，当我需要通过Web服务发送字典对象时，我最终自己包装了Dictionary <>对象并添加了对的支持IXMLSerializable。

/// <summary>
/// Represents an XML serializable collection of keys and values.
/// </summary>
/// <typeparam name="TKey">The type of the keys in the dictionary.</typeparam>
/// <typeparam name="TValue">The type of the values in the dictionary.</typeparam>
[XmlRoot("dictionary")]
public class SerializableDictionary<TKey, TValue> : Dictionary<TKey, TValue>, IXmlSerializable
{
    #region Constants

    /// <summary>
    /// The default XML tag name for an item.
    /// </summary>
    private const string DEFAULT_ITEM_TAG = "Item";

    /// <summary>
    /// The default XML tag name for a key.
    /// </summary>
    private const string DEFAULT_KEY_TAG = "Key";

    /// <summary>
    /// The default XML tag name for a value.
    /// </summary>
    private const string DEFAULT_VALUE_TAG = "Value";

    #endregion

    #region Protected Properties

    /// <summary>
    /// Gets the XML tag name for an item.
    /// </summary>
    protected virtual string ItemTagName
    {
        get
        {
            return DEFAULT_ITEM_TAG;
        }
    }

    /// <summary>
    /// Gets the XML tag name for a key.
    /// </summary>
    protected virtual string KeyTagName
    {
        get
        {
            return DEFAULT_KEY_TAG;
        }
    }

    /// <summary>
    /// Gets the XML tag name for a value.
    /// </summary>
    protected virtual string ValueTagName
    {
        get
        {
            return DEFAULT_VALUE_TAG;
        }
    }

    #endregion

    #region Public Methods

    /// <summary>
    /// Gets the XML schema for the XML serialization.
    /// </summary>
    /// <returns>An XML schema for the serialized object.</returns>
    public XmlSchema GetSchema()
    {
        return null;
    }

    /// <summary>
    /// Deserializes the object from XML.
    /// </summary>
    /// <param name="reader">The XML representation of the object.</param>
    public void ReadXml(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 != XmlNodeType.EndElement)
        {
            reader.ReadStartElement(ItemTagName);

            reader.ReadStartElement(KeyTagName);
            TKey key = (TKey)keySerializer.Deserialize(reader);
            reader.ReadEndElement();

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

            this.Add(key, value);

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

        reader.ReadEndElement();
    }

    /// <summary>
    /// Serializes this instance to XML.
    /// </summary>
    /// <param name="writer">The writer to serialize to.</param>
    public void WriteXml(XmlWriter writer)
    {
        XmlSerializer keySerializer = new XmlSerializer(typeof(TKey));
        XmlSerializer valueSerializer = new XmlSerializer(typeof(TValue));

        foreach (TKey key in this.Keys)
        {
            writer.WriteStartElement(ItemTagName);

            writer.WriteStartElement(KeyTagName);
            keySerializer.Serialize(writer, key);
            writer.WriteEndElement();

            writer.WriteStartElement(ValueTagName);
            TValue value = this[key];
            valueSerializer.Serialize(writer, value);
            writer.WriteEndElement();

            writer.WriteEndElement();
        }
    }

    #endregion
}

回答

KeyedCollection是一种字典类型，可以直接序列化为xml，而无需任何废话。唯一的问题是，我们必须通过以下方式访问值：coll [" key"]。Value;

回答

我们将在此MSDN博客文章中找到无法对KeyValuePairs进行序列化的原因。

Struct答案是最简单的解决方案，但不是唯一的解决方案。一个"更好"的解决方案是编写一个可序列化的Custom KeyValurPair类。