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,但无法在Web服务中正确序列化。在Web服务中,“键”和“值”属性未序列化,因此除非有人知道解决此问题的方法,否则该类无用。
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。
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,但无法在Web服务中正确序列化。在Web服务中,“键”和“值”属性未序列化,因此除非有人知道解决此问题的方法,否则该类无用。
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。
Answers:
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;}
}
'AttributeCollection' does not contain a definition for 'Where' and the best extension method overload 'Queryable.Where<KeyValuePair<string, object>>(IQueryable<KeyValuePair<string, object>>, Expression<Func<KeyValuePair<string, object>, bool>>)' requires a receiver of type 'IQueryable<KeyValuePair<string, object>>'
我不认为Dictionary<>XML本身不是可序列化的,当我需要通过Web服务发送字典对象时,我最终自己包装了该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
}
您将在此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。一种“更好”的解决方案是编写一个可序列化的Custom KeyValurPair类。
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,您必须通过以下方式访问值:coll [“ key”]。Value;
XmlSerializer不适用于Dictionary。哦,KeyValuePairs也有问题
http://www.codeproject.com/Tips/314447/XmlSerializer-doesnt-work-with-Dictionaries-Oh-and
使用DataContractSerializer,因为它可以处理键值对。
public static string GetXMLStringFromDataContract(object contractEntity)
{
using (System.IO.MemoryStream writer = new System.IO.MemoryStream())
{
var dataContractSerializer = new DataContractSerializer(contractEntity.GetType());
dataContractSerializer.WriteObject(writer, contractEntity);
writer.Position = 0;
var streamReader = new System.IO.StreamReader(writer);
return streamReader.ReadToEnd();
}
}
DataTable是我最喜欢的(仅)包装要序列化为JSON的数据的集合,因为它很容易扩展,而无需额外的内容struct,并且行为类似于Tuple<>[]
也许不是最干净的方法,但我更喜欢直接在类(应序列化)中包含并使用它,而不是声明一个新的 struct
class AnyClassToBeSerialized
{
public DataTable KeyValuePairs { get; }
public AnyClassToBeSerialized
{
KeyValuePairs = new DataTable();
KeyValuePairs.Columns.Add("Key", typeof(string));
KeyValuePairs.Columns.Add("Value", typeof(string));
}
public void AddEntry(string key, string value)
{
DataRow row = KeyValuePairs.NewRow();
row["Key"] = key; // "Key" & "Value" used only for example
row["Value"] = value;
KeyValuePairs.Rows.Add(row);
}
}