Newtonsoft.Json\Converters\KeyValuePairConverter.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using Newtonsoft.Json.Utilities;

using System.Reflection;

namespace Newtonsoft.Json.Converters

{

  /// <summary>

  /// Converts a <see cref="KeyValuePair{TKey,TValue}"/> to and from JSON.

  /// </summary>

  public class KeyValuePairConverter : JsonConverter

  {

    /// <summary>

    /// Writes the JSON representation of the object.

    /// </summary>

    /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>

    /// <param name="value">The value.</param>

    /// <param name="serializer">The calling serializer.</param>

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

    {

      Type t = value.GetType();

      PropertyInfo keyProperty = t.GetProperty("Key");

      PropertyInfo valueProperty = t.GetProperty("Value");

      writer.WriteStartObject();

      writer.WritePropertyName("Key");

      serializer.Serialize(writer, ReflectionUtils.GetMemberValue(keyProperty, value));

      writer.WritePropertyName("Value");

      serializer.Serialize(writer, ReflectionUtils.GetMemberValue(valueProperty, value));

      writer.WriteEndObject();

    }

    /// <summary>

    /// Reads the JSON representation of the object.

    /// </summary>

    /// <param name="reader">The <see cref="JsonReader"/> to read from.</param>

    /// <param name="objectType">Type of the object.</param>

    /// <param name="existingValue">The existing value of object being read.</param>

    /// <param name="serializer">The calling serializer.</param>

    /// <returns>The object value.</returns>

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

    {

      IList<Type> genericArguments = objectType.GetGenericArguments();

      Type keyType = genericArguments[0];

      Type valueType = genericArguments[1];

      reader.Read();

      reader.Read();

      object key = serializer.Deserialize(reader, keyType);

      reader.Read();

      reader.Read();

      object value = serializer.Deserialize(reader, valueType);

      reader.Read();

      return ReflectionUtils.CreateInstance(objectType, key, value);

    }

    /// <summary>

    /// Determines whether this instance can convert the specified object type.

    /// </summary>

    /// <param name="objectType">Type of the object.</param>

    /// <returns>

    /// 	<c>true</c> if this instance can convert the specified object type; otherwise, <c>false</c>.

    /// </returns>

    public override bool CanConvert(Type objectType)

    {

      if (objectType.IsValueType && objectType.IsGenericType)

        return (objectType.GetGenericTypeDefinition() == typeof (KeyValuePair<,>));

      return false;

    }

  }

}