DataTableConverter
Converts a DataTable to and from JSON.
using Newtonsoft.Json.Serialization;
using Newtonsoft.Json.Utilities;
using System;
using System.Collections.Generic;
using System.Data;
using System.Globalization;
namespace Newtonsoft.Json.Converters
{
public class DataTableConverter : JsonConverter
{
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
DataTable dataTable = (DataTable)value;
DefaultContractResolver defaultContractResolver = serializer.ContractResolver as DefaultContractResolver;
writer.WriteStartArray();
foreach (DataRow row in dataTable.Rows) {
writer.WriteStartObject();
foreach (DataColumn column in row.Table.Columns) {
if (serializer.NullValueHandling != NullValueHandling.Ignore || (row[column] != null && row[column] != DBNull.Value)) {
writer.WritePropertyName((defaultContractResolver != null) ? defaultContractResolver.GetResolvedPropertyName(column.ColumnName) : column.ColumnName);
serializer.Serialize(writer, row[column]);
}
}
writer.WriteEndObject();
}
writer.WriteEndArray();
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
DataTable dataTable = existingValue as DataTable;
if (dataTable == null)
dataTable = ((objectType == typeof(DataTable)) ? new DataTable() : ((DataTable)Activator.CreateInstance(objectType)));
if (reader.TokenType == JsonToken.PropertyName) {
dataTable.TableName = (string)reader.Value;
reader.Read();
}
if (reader.TokenType == JsonToken.StartArray)
reader.Read();
while (reader.TokenType != JsonToken.EndArray) {
CreateRow(reader, dataTable);
reader.Read();
}
return dataTable;
}
private static void CreateRow(JsonReader reader, DataTable dt)
{
DataRow dataRow = dt.NewRow();
reader.Read();
while (reader.TokenType == JsonToken.PropertyName) {
string text = (string)reader.Value;
reader.Read();
DataColumn dataColumn = dt.Columns[text];
if (dataColumn == null) {
Type columnDataType = GetColumnDataType(reader);
dataColumn = new DataColumn(text, columnDataType);
dt.Columns.Add(dataColumn);
}
if (dataColumn.DataType == typeof(DataTable)) {
if (reader.TokenType == JsonToken.StartArray)
reader.Read();
DataTable dataTable = new DataTable();
while (reader.TokenType != JsonToken.EndArray) {
CreateRow(reader, dataTable);
reader.Read();
}
dataRow[text] = dataTable;
} else if (dataColumn.DataType.IsArray) {
if (reader.TokenType == JsonToken.StartArray)
reader.Read();
List<object> list = new List<object>();
while (reader.TokenType != JsonToken.EndArray) {
list.Add(reader.Value);
reader.Read();
}
Array array = Array.CreateInstance(dataColumn.DataType.GetElementType(), list.Count);
Array.Copy(list.ToArray(), array, list.Count);
dataRow[text] = array;
} else {
dataRow[text] = (reader.Value ?? DBNull.Value);
}
reader.Read();
}
dataRow.EndEdit();
dt.Rows.Add(dataRow);
}
private static Type GetColumnDataType(JsonReader reader)
{
JsonToken tokenType = reader.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);
case JsonToken.StartArray: {
reader.Read();
if (reader.TokenType == JsonToken.StartObject)
return typeof(DataTable);
Type columnDataType = GetColumnDataType(reader);
return columnDataType.MakeArrayType();
}
default:
throw new JsonException("Unexpected JSON token while reading DataTable: {0}".FormatWith(CultureInfo.InvariantCulture, tokenType));
}
}
public override bool CanConvert(Type valueType)
{
return typeof(DataTable).IsAssignableFrom(valueType);
}
}
}