using System;
using System.Collections.Generic;
using System.Text;
using System.Data;
using System.Reflection;
using System.Collections;
using System.Data.Common;
 
public class ConvertJson
{
  #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
}