JsonHelper

using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Reflection;
using System.Collections;
using System.Data.Common;
    //JSON转换类 
    public class JsonHelper
    {
        #region 私有方法
        /// <summary> 
        /// 过滤特殊字符 
        /// </summary> 
        private static string String2Json(String s)
        {
            StringBuilder sb = new StringBuilder();
            for (int i = 0; i < s.Length; i++)
            {
                char c = s.ToCharArray()[i];
                switch (c)
                {
                    case '\"':
                        sb.Append("\\\""); break;
                    case '\\':
                        sb.Append("\\\\"); break;
                    case '/':
                        sb.Append("\\/"); break;
                    case '\b':
                        sb.Append("\\b"); break;
                    case '\f':
                        sb.Append("\\f"); break;
                    case '\n':
                        sb.Append("\\n"); break;
                    case '\r':
                        sb.Append("\\r"); break;
                    case '\t':
                        sb.Append("\\t"); break;
                    default:
                        sb.Append(c); break;
                }
            }
            return sb.ToString();
        }

        /// <summary> 
        /// 格式化字符型、日期型、布尔型 
        /// </summary> 
        private static string StringFormat(string str, Type type)
        {
            if (type == typeof(string))
            {
                str = String2Json(str);
                str = "\"" + str + "\"";
            }
            else if (type == typeof(DateTime))
            {
                str = "\"" + str + "\"";
            }
            else if (type == typeof(bool))
            {
                str = str.ToLower();
            }
            else if (type != typeof(string) && string.IsNullOrEmpty(str))
            {
                str = "\"" + str + "\"";
            }
            return str;
        }
        #endregion

        #region List转换成Json
        /// <summary> 
        /// List转换成Json 
        /// </summary> 
        public static string ListToJson<T>(IList<T> list)
        {
            object obj = list[0];
            return ListToJson<T>(list, obj.GetType().Name);
        }

        /// <summary> 
        /// List转换成Json  
        /// </summary> 
        public static string ListToJson<T>(IList<T> list, string jsonName)
        {
            StringBuilder Json = new StringBuilder();
            if (string.IsNullOrEmpty(jsonName)) jsonName = list[0].GetType().Name;
            Json.Append("{\"" + jsonName + "\":[");
            if (list.Count > 0)
            {
                for (int i = 0; i < list.Count; i++)
                {
                    T obj = Activator.CreateInstance<T>();
                    PropertyInfo[] pi = obj.GetType().GetProperties();
                    Json.Append("{");
                    for (int j = 0; j < pi.Length; j++)
                    {
                        Type type = pi[j].GetValue(list[i], null).GetType();
                        Json.Append("\"" + pi[j].Name.ToString() + "\":" + StringFormat(pi[j].GetValue(list[i], null).ToString(), type));

                        if (j < pi.Length - 1)
                        {
                            Json.Append(",");
                        }
                    }
                    Json.Append("}");
                    if (i < list.Count - 1)
                    {
                        Json.Append(",");
                    }
                }
            }
            Json.Append("]}");
            return Json.ToString();
        }
        #endregion

        #region 对象转换为Json
        /// <summary>  
        /// 对象转换为Json  
        /// </summary>  
        /// <param name="jsonObject">对象</param>  
        /// <returns>Json字符串</returns>  
        public static string ToJson(object jsonObject)
        {
            string jsonString = "{";
            PropertyInfo[] propertyInfo = jsonObject.GetType().GetProperties();
            for (int i = 0; i < propertyInfo.Length; i++)
            {
                object objectValue = propertyInfo[i].GetGetMethod().Invoke(jsonObject, null);
                string value = string.Empty;
                if (objectValue is DateTime || objectValue is Guid || objectValue is TimeSpan)
                {
                    value = "'" + objectValue.ToString() + "'";
                }
                else if (objectValue is string)
                {
                    value = "'" + ToJson(objectValue.ToString()) + "'";
                }
                else if (objectValue is IEnumerable)
                {
                    value = ToJson((IEnumerable)objectValue);
                }
                else
                {
                    value = ToJson(objectValue.ToString());
                }
                jsonString += "\"" + ToJson(propertyInfo[i].Name) + "\":" + value + ",";
            }
            jsonString.Remove(jsonString.Length - 1, jsonString.Length);
            return jsonString + "}";
        }
        #endregion

        #region 对象集合转换Json
        /// <summary>  
        /// 对象集合转换Json  
        /// </summary>  
        /// <param name="array">集合对象</param>  
        /// <returns>Json字符串</returns>  
        public static string ToJson(IEnumerable array)
        {
            string jsonString = "[";
            foreach (object item in array)
            {
                jsonString += ToJson(item) + ",";
            }
            jsonString.Remove(jsonString.Length - 1, jsonString.Length);
            return jsonString + "]";
        }
        #endregion

        #region 普通集合转换Json
        /// <summary>  
        /// 普通集合转换Json  
        /// </summary>  
        /// <param name="array">集合对象</param>  
        /// <returns>Json字符串</returns>  
        public static string ToArrayString(IEnumerable array)
        {
            string jsonString = "[";
            foreach (object item in array)
            {
                jsonString = ToJson(item.ToString()) + ",";
            }
            jsonString.Remove(jsonString.Length - 1, jsonString.Length);
            return jsonString + "]";
        }
        #endregion

        #region  DataSet转换为Json
        /// <summary>  
        /// DataSet转换为Json  
        /// </summary>  
        /// <param name="dataSet">DataSet对象</param>  
        /// <returns>Json字符串</returns>  
        public static string ToJson(DataSet dataSet)
        {
            string jsonString = "{";
            foreach (DataTable table in dataSet.Tables)
            {
                jsonString += "\"" + table.TableName + "\":" + ToJson(table) + ",";
            }
            jsonString = jsonString.TrimEnd(',');
            return jsonString + "}";
        }
        #endregion 

        #region Datatable转换为Json 
        /// <summary>  
        /// Datatable转换为Json  
        /// </summary>  
        /// <param name="table">Datatable对象</param>  
        /// <returns>Json字符串</returns>  
        public static string ToJson(DataTable dt) 
        { 
            StringBuilder jsonString = new StringBuilder(); 
            jsonString.Append("["); 
            DataRowCollection drc = dt.Rows; 
            for (int i = 0; i < drc.Count; i++) 
            { 
                jsonString.Append("{"); 
                for (int j = 0; j < dt.Columns.Count; j++) 
                { 
                    string strKey = dt.Columns[j].ColumnName; 
                    string strValue = drc[i][j].ToString(); 
                    Type type = dt.Columns[j].DataType; 
                    jsonString.Append("\"" + strKey + "\":"); 
                    strValue = StringFormat(strValue, type); 
                    if (j < dt.Columns.Count - 1) 
                    { 
                        jsonString.Append(strValue + ","); 
                    } 
                    else
                    { 
                        jsonString.Append(strValue); 
                    } 
                } 
                jsonString.Append("},"); 
            } 
            jsonString.Remove(jsonString.Length - 1, 1); 
            jsonString.Append("]"); 
            return jsonString.ToString(); 
        } 
  
        /// <summary> 
        /// DataTable转换为Json  
        /// </summary> 
        public static string ToJson(DataTable dt, string jsonName) 
        { 
            StringBuilder Json = new StringBuilder(); 
            if (string.IsNullOrEmpty(jsonName)) jsonName = dt.TableName; 
            Json.Append("{\"" + jsonName + "\":["); 
            if (dt.Rows.Count > 0) 
            { 
                for (int i = 0; i < dt.Rows.Count; i++) 
                { 
                    Json.Append("{"); 
                    for (int j = 0; j < dt.Columns.Count; j++) 
                    { 
                        Type type = dt.Rows[i][j].GetType(); 
                        Json.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + StringFormat(dt.Rows[i][j].ToString(), type)); 
                        if (j < dt.Columns.Count - 1) 
                        { 
                            Json.Append(","); 
                        } 
                    } 
                    Json.Append("}"); 
                    if (i < dt.Rows.Count - 1) 
                    { 
                        Json.Append(","); 
                    } 
                } 
            } 
            Json.Append("]}"); 
            return Json.ToString(); 
        } 
        #endregion 
  
        #region DataReader转换为Json 
        /// <summary>  
        /// DataReader转换为Json  
        /// </summary>  
        /// <param name="dataReader">DataReader对象</param>  
        /// <returns>Json字符串</returns>  
        public static string ToJson(DbDataReader dataReader) 
        { 
            StringBuilder jsonString = new StringBuilder(); 
            jsonString.Append("["); 
            while (dataReader.Read()) 
            { 
                jsonString.Append("{"); 
                for (int i = 0; i < dataReader.FieldCount; i++) 
                { 
                    Type type = dataReader.GetFieldType(i); 
                    string strKey = dataReader.GetName(i); 
                    string strValue = dataReader[i].ToString(); 
                    jsonString.Append("\"" + strKey + "\":"); 
                    strValue = StringFormat(strValue, type); 
                    if (i < dataReader.FieldCount - 1) 
                    { 
                        jsonString.Append(strValue + ","); 
                    } 
                    else
                    { 
                        jsonString.Append(strValue); 
                    } 
                } 
                jsonString.Append("},"); 
            } 
            dataReader.Close(); 
            jsonString.Remove(jsonString.Length - 1, 1); 
            jsonString.Append("]"); 
            return jsonString.ToString(); 
        } 
        #endregion 
    }