C#中的DataSet、string、DataTable、对象转换成Json的实现代码

c#中对象，字符串，datatable、datareader、dataset，对象集合转换成json字符串方法。

public class convertjson
 {
  #region 私有方法
  /// <summary>
  /// 过滤特殊字符
  /// </summary>
  /// <param name="s">字符串</param>
  /// <returns>json字符串</returns>
  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>
  /// <param name="str"></param>
  /// <param name="type"></param>
  /// <returns></returns>
  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转换为json
  /// </summary>
  /// <typeparam name="t"></typeparam>
  /// <param name="list"></param>
  /// <returns></returns>
  public static string listtojson<t>(ilist<t> list)
  {
   object obj = list[0];
   return listtojson<t>(list, obj.gettype().name);
  }
  /// <summary>
  /// list转换为json
  /// </summary>
  /// <typeparam name="t1"></typeparam>
  /// <param name="list"></param>
  /// <param name="p"></param>
  /// <returns></returns>
  private 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">json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 对象集合转换为json
  /// <summary>
  /// 对象集合转换为json
  /// </summary>
  /// <param name="array">对象集合</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
 }