Newtonsoft.Json\Converters\DataTableConverter.cs

#region License

// Copyright (c) 2007 James Newton-King

//

// Permission is hereby granted, free of charge, to any person

// obtaining a copy of this software and associated documentation

// files (the "Software"), to deal in the Software without

// restriction, including without limitation the rights to use,

// copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the

// Software is furnished to do so, subject to the following

// conditions:

//

// The above copyright notice and this permission notice shall be

// included in all copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,

// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES

// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND

// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT

// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,

// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

// OTHER DEALINGS IN THE SOFTWARE.

#endregion

#if !SILVERLIGHT

using System;

using System.Data;

namespace Newtonsoft.Json.Converters

{

  /// <summary>

  /// Converts a <see cref="DataTable"/> to and from JSON.

  /// </summary>

  public class DataTableConverter : 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)

    {

      DataTable table = (DataTable)value;

      writer.WriteStartArray();

      foreach (DataRow row in table.Rows)

      {

        writer.WriteStartObject();

        foreach (DataColumn column in row.Table.Columns)

        {

          writer.WritePropertyName(column.ColumnName);

          serializer.Serialize(writer, row[column]);

        }

        writer.WriteEndObject();

      }

      writer.WriteEndArray();

    }

    /// <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)

    {

      DataTable dt;

      if (reader.TokenType == JsonToken.PropertyName)

      {

        dt = new DataTable((string)reader.Value);

        reader.Read();

      }

      else

      {

        dt = new DataTable();

      }

      reader.Read();

      while (reader.TokenType == JsonToken.StartObject)

      {

        DataRow dr = dt.NewRow();

        reader.Read();

        while (reader.TokenType == JsonToken.PropertyName)

        {

          string columnName = (string) reader.Value;

          reader.Read();

          if (!dt.Columns.Contains(columnName))

          {

            Type columnType = GetColumnDataType(reader.TokenType);

            dt.Columns.Add(new DataColumn(columnName, columnType));

          }

          dr[columnName] = reader.Value;

          reader.Read();

        }

        dr.EndEdit();

        dt.Rows.Add(dr);

        reader.Read();

      }

      reader.Read();

      return dt;

    }

    private static Type GetColumnDataType(JsonToken tokenType)

    {

      switch (tokenType)

      {

        case JsonToken.Integer:

          return typeof (long);

        case JsonToken.Float:

          return typeof (double);

        case JsonToken.String:

        case JsonToken.Null:

        case JsonToken.Undefined:

          return typeof (string);

        case JsonToken.Boolean:

          return typeof (bool);

        case JsonToken.Date:

          return typeof (DateTime);

        default:

          throw new ArgumentOutOfRangeException();

      }

    }

    /// <summary>

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

    /// </summary>

    /// <param name="valueType">Type of the value.</param>

    /// <returns>

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

    /// </returns>

    public override bool CanConvert(Type valueType)

    {

      return (valueType == typeof(DataTable));

    }

  }

}

#endif