ASP.NET中各种连接数据库的配置的方法及json数据转换

 <connectionstrings>
 <add name="conn" connectionstring="server=.;database=demo;uid=sa;pwd=123456" providername="system.data.sqlclient"/>
 </connectionstrings> 

 <connectionstrings>
 <add name="conn" connectionstring="provider=microsoft.jet.oledb.4.0; data source={0}app_data/demo.mdb" providername="system.data.oledb"/>
 </connectionstrings> 

 <connectionstrings>
 <add name="conn" connectionstring="provider=microsoft.jet.oledb.4.0; data source={0}app_data/demo.mdb" providername="system.data.oledb"/>
 </connectionstrings> 

 <connectionstrings>
 <add name="conn" connectionstring="provider=msdaora;data source=demo;user id=sa;password=123456;" providername="system.data.oracleclient"/>
 </connectionstrings> 

 <connectionstrings>
 <add name="conn" connectionstring="data source={0}app_data/demo.db;failifmissing=false" providername="system.data.sqlite"/>
 </connectionstrings> 

 <connectionstrings>
 <add name="conn" connectionstring="host=127.0.0.1;port=3306;database=mysql;uid=sa;pwd=12346" providername="mysql.data.mysqlclient"/>
 </connectionstrings> 

using system;
using system.collections.generic;
using system.data;
using system.linq;
using system.reflection;
using system.text;
using system.web;
using system.web.script.serialization;

namespace role.dal
{
 public class json
 {
  public json() { }

  /// <summary>
  ///将datatable数据转换成json数据, 字符串拼接写成的
  /// </summary>
  /// <param name="jsonname">json名称。没发现什么作用</param>
  /// <param name="dt">得到的数据表</param>
  /// <returns></returns>
  public string datatabletojson(string jsonname, datatable dt)
  {
   stringbuilder json = new stringbuilder();
   json.append("[");
   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++)
     {
      json.append(dt.columns[j].columnname.tostring() + ":\"" + dt.rows[i][j].tostring() + "\"");
      if (j < dt.columns.count - 1)
      {
       json.append(",");
      }
     }
     json.append("}");
     if (i < dt.rows.count - 1)
     {
      json.append(",");
     }
    }
   }
   json.append("]");
   return json.tostring();
  }


  /// <summary>
  /// 列表数据转换到json数据;字符串拼接写成的，太难
  /// </summary>
  /// <typeparam name="t"></typeparam>
  /// <param name="jsonname">json名称。没发现什么作用</param>
  /// <param name="il"></param>
  /// <returns></returns>
  public string objecttojson<t>(string jsonname, ilist<t> il)
  {
   stringbuilder json = new stringbuilder();
   json.append("[");
   if (il.count > 0)
   {
    for (int i = 0; i < il.count; i++)
    {
     t obj = activator.createinstance<t>();
     type type = obj.gettype();
     propertyinfo[] pis = type.getproperties();
     json.append("{");
     for (int j = 0; j < pis.length; j++)
     {
      json.append(pis[j].name.tostring() + ":\"" + pis[j].getvalue(il[i], null) + "\"");
      if (j < pis.length - 1)
      {
       json.append(",");
      }
     }
     json.append("}");
     if (i < il.count - 1)
     {
      json.append(",");
     }
    }
   }
   json.append("]");
   return json.tostring();
  }

  /// <summary>
  /// 将datatable转化为自定义json数据
  /// </summary>
  /// <param name="dt">数据表</param>
  /// <returns>json字符串</returns> 
  public static string datatabletojson(datatable dt)
  {
   stringbuilder jsonstring = new stringbuilder();
   if (dt != null && dt.rows.count > 0)
   {
    list<dictionary<string, string>> list = new list<dictionary<string, string>>();
    for (int i = 0; i < dt.rows.count; i++)
    {
     dictionary<string, string> dict = new dictionary<string, string>();
     for (int j = 0; j < dt.columns.count; j++)
     {
      dict.add(dt.columns[j].columnname, dt.rows[i][j].tostring());
     }
     list.add(dict);
    }
    javascriptserializer jsonserializer = new javascriptserializer();
    return jsonserializer.serialize(list);
   }
   else
   {
    return "{}";
   }
  }

  /// <summary>
  /// 将datatable转换为json 
  /// </summary>
  /// <param name="dtb">dt</param>
  /// <returns>json字符串</returns>
  public static string dtb2json(datatable dtb)
  {
   javascriptserializer jss = new javascriptserializer();
   system.collections.arraylist dic = new system.collections.arraylist();
   if (dtb != null && dtb.rows.count > 0)
   {
    foreach (datarow dr in dtb.rows)
    {
     system.collections.generic.dictionary<string, object> drow = new system.collections.generic.dictionary<string, object>();
     foreach (datacolumn dc in dtb.columns)
     {
      drow.add(dc.columnname, dr[dc.columnname]);
     }
     dic.add(drow);
    }
    //序列化 
    return jss.serialize(dic);
   }
   else
   {
    return "{}";
   }
  }

 }
}