波斯马BOSSMA Information Technology

在目前web开发的应用中，ajax效果被广泛的应用，需要在在客户端和服务器端频繁的传送数据，json格式的数据被javascript天然的支持，具有良好的编程支持和更好的效率。在以前的开发中，都是每次获取数据的时候构造json数据，没有达到重用和封装的目标。最近参考网上的资源，主要是Json.Net和Rick Strahl’s Web Log，写了一个json的帮助类。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using Newtonsoft.Json;
using System.Data;

namespace VeryCodes.Common
{
??? /// <summary>
??? /// Json处理类
??? /// </summary>
??? public class JsonHelper
??? {
??????? /// <summary>
??????? /// 序列化数据为Json数据格式.
??????? /// </summary>
??????? /// <param name="value">The value.</param>
??????? /// <returns></returns>
??????? public static string Serialize(object value)
??????? {
??????????? Type type = value.GetType();

??????????? Newtonsoft.Json.JsonSerializer json = new Newtonsoft.Json.JsonSerializer();

??????????? json.NullValueHandling = NullValueHandling.Ignore;

??????????? json.ObjectCreationHandling = Newtonsoft.Json.ObjectCreationHandling.Replace;
??????????? json.MissingMemberHandling = Newtonsoft.Json.MissingMemberHandling.Ignore;
??????????? json.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;

??????????? if (type == typeof(DataRow))
??????????????? json.Converters.Add(new DataRowConverter());
??????????? else if (type == typeof(DataTable))
??????????????? json.Converters.Add(new DataTableConverter());
??????????? else if (type == typeof(DataSet))
??????????????? json.Converters.Add(new DataSetConverter());

??????????? StringWriter sw = new StringWriter();
??????????? Newtonsoft.Json.JsonTextWriter writer = new JsonTextWriter(sw);
??????????? //writer.Formatting = Formatting.Indented;
??????????? writer.Formatting = Formatting.None;

??????????? writer.QuoteChar = '"';
??????????? json.Serialize(writer, value);

??????????? string output = sw.ToString();
??????????? writer.Close();
??????????? sw.Close();

??????????? return output;
??????? }

??????? /// <summary>
??????? /// 反序列化Json数据格式.
??????? /// </summary>
??????? /// <param name="jsonText">The json text.</param>
??????? /// <param name="valueType">Type of the value.</param>
??????? /// <returns></returns>
??????? public static object Deserialize(string jsonText, Type valueType)
??????? {
??????????? Newtonsoft.Json.JsonSerializer json = new Newtonsoft.Json.JsonSerializer();

??????????? json.NullValueHandling = Newtonsoft.Json.NullValueHandling.Ignore;
??????????? json.ObjectCreationHandling = Newtonsoft.Json.ObjectCreationHandling.Replace;
??????????? json.MissingMemberHandling = Newtonsoft.Json.MissingMemberHandling.Ignore;
??????????? json.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;

??????????? StringReader sr = new StringReader(jsonText);
??????????? Newtonsoft.Json.JsonTextReader reader = new JsonTextReader(sr);
??????????? object result = json.Deserialize(reader, valueType);
??????????? reader.Close();

??????????? return result;
??????? }

??????? /// <summary>
??????? /// 遍历DataTable的行和列生成Json，可控制性较差
??????? /// </summary>
??????? /// <param name="dt"></param>
??????? /// <returns></returns>
??????? public static string DataTable2Json(DataTable dt)
??????? {
??????????? StringBuilder jsonBuilder = new StringBuilder();
??????????? jsonBuilder.Append("{\"");
??????????? jsonBuilder.Append(dt.TableName);
??????????? jsonBuilder.Append("\":[");
??????????? for (int i = 0; i < dt.Rows.Count; i++)
??????????? {
??????????????? jsonBuilder.Append("{");
??????????????? for (int j = 0; j < dt.Columns.Count; j++)
??????????????? {
??????????????????? jsonBuilder.Append("\"");
??????????????????? jsonBuilder.Append(dt.Columns[j].ColumnName);
??????????????????? jsonBuilder.Append("\":\"");
??????????????????? jsonBuilder.Append(dt.Rows[i][j].ToString());
??????????????????? jsonBuilder.Append("\",");
??????????????? }
??????????????? jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
??????????????? jsonBuilder.Append("},");
??????????? }
??????????? jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
??????????? jsonBuilder.Append("]");
??????????? jsonBuilder.Append("}");
??????????? return jsonBuilder.ToString();
??????? }

??????? /// <summary>
??????? /// 遍历DataTable的行和列生成Json，控制数据列，专门为FlexiGrid提供便捷的数据源生成
??????? /// </summary>
??????? /// <param name="dt">DataTable对象</param>
??????? /// <param name="cols">Json中的数据列</param>
??????? /// <returns></returns>
??????? public static string Json4FlexiGrid(DataTable dt, string cols)
??????? {
??????????? StringBuilder jsonBuilder = new StringBuilder();
??????????? string[] colarr = cols.Split(',');

??????????? if (dt.Rows.Count > 0)
??????????? {
??????????????? for (int i = 0; i < dt.Rows.Count; i++)
??????????????? {
??????????????????? jsonBuilder.Append("{");
??????????????????? jsonBuilder.Append("\"id\":");
??????????????????? jsonBuilder.Append("\"");
??????????????????? jsonBuilder.Append(dt.Rows[i]["ID"].ToString());
??????????????????? jsonBuilder.Append("\",\"cell\":[");
??????????????????? foreach (string col in colarr)
??????????????????? {
??????????????????????? jsonBuilder.Append("\"");
??????????????????????? jsonBuilder.Append(dt.Rows[i][col].ToString());
??????????????????????? jsonBuilder.Append("\",");
??????????????????? }
??????????????????? jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
??????????????????? jsonBuilder.Append("]},");
??????????????? }
??????????????? jsonBuilder.Remove(jsonBuilder.Length - 1, 1);
??????????? }

??????????? return jsonBuilder.ToString();
??????? }
??? }

??? /// <summary>
??? /// Converts a <see cref="DataRow"/> object to and from JSON.
??? /// </summary>
??? public class DataRowConverter : JsonConverter
??? {
??????? /// <summary>
??????? /// Writes the JSON representation of the object.
??????? /// </summary>
??????? /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>
??????? /// <param name="dataRow">The data row.</param>
??????? /// <param name="ser">The JsonSerializer 对象.</param>
??????? public override void WriteJson(JsonWriter writer, object dataRow, JsonSerializer ser)
??????? {
??????????? DataRow row = dataRow as DataRow;

??????????? writer.WriteStartObject();
??????????? foreach (DataColumn column in row.Table.Columns)
??????????? {
??????????????? writer.WritePropertyName(column.ColumnName);
??????????????? ser.Serialize(writer, row[column]);
??????????? }
??????????? writer.WriteEndObject();
??????? }

??????? /// <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 typeof(DataRow).IsAssignableFrom(valueType);
??????? }

??????? /// <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>
??????? /// <returns>The object value.</returns>
??????? public override object ReadJson(JsonReader reader, Type objectType, JsonSerializer ser)
??????? {
??????????? throw new NotImplementedException();
??????? }
??? }

??? /// <summary>
??? /// Converts a DataTable to JSON. Note no support for deserialization
??? /// </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="dataTable">The data table.</param>
??????? /// <param name="ser">The JsonSerializer Object.</param>
??????? public override void WriteJson(JsonWriter writer, object dataTable, JsonSerializer ser)
??????? {
??????????? DataTable table = dataTable as DataTable;
??????????? DataRowConverter converter = new DataRowConverter();

??????????? writer.WriteStartObject();

??????????? writer.WritePropertyName("Rows");
??????????? writer.WriteStartArray();

??????????? foreach (DataRow row in table.Rows)
??????????? {
??????????????? converter.WriteJson(writer, row, ser);
??????????? }

??????????? writer.WriteEndArray();
??????????? writer.WriteEndObject();
??????? }

??????? /// <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 typeof(DataTable).IsAssignableFrom(valueType);
??????? }

??????? /// <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>
??????? /// <returns>The object value.</returns>
??????? public override object ReadJson(JsonReader reader, Type objectType, JsonSerializer ser)
??????? {
??????????? throw new NotImplementedException();
??????? }
??? }

??? /// <summary>
??? /// Converts a <see cref="DataSet"/> object to JSON. No support for reading.
??? /// </summary>
??? public class DataSetConverter : JsonConverter
??? {
??????? /// <summary>
??????? /// Writes the JSON representation of the object.
??????? /// </summary>
??????? /// <param name="writer">The <see cref="JsonWriter"/> to write to.</param>
??????? /// <param name="dataset">The dataset.</param>
??????? /// <param name="ser">The JsonSerializer Object.</param>
??????? public override void WriteJson(JsonWriter writer, object dataset, JsonSerializer ser)
??????? {
??????????? DataSet dataSet = dataset as DataSet;

??????????? DataTableConverter converter = new DataTableConverter();

??????????? writer.WriteStartObject();

??????????? writer.WritePropertyName("Tables");
??????????? writer.WriteStartArray();

??????????? foreach (DataTable table in dataSet.Tables)
??????????? {
??????????????? converter.WriteJson(writer, table, ser);
??????????? }
??????????? writer.WriteEndArray();
??????????? writer.WriteEndObject();
??????? }

??????? /// <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 typeof(DataSet).IsAssignableFrom(valueType);
??????? }

??????? /// <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>
??????? /// <returns>The object value.</returns>
??????? public override object ReadJson(JsonReader reader, Type objectType, JsonSerializer ser)
??????? {
??????????? throw new NotImplementedException();
??????? }
??? }
}

flexigrid是一个优秀的javascript表格控件，通过Json4FlexiGrid方法，我们可以很方便的为flexigrid提供数据源。
JsonConverter来源于Newtonsoft.Json，这是一个Json的开源项目，点击这里查看项目信息。

关键字: flexigrid json JsonConverter jsonhelper