Configure database connection and json conversion

This article mainly introduces the configuration methods of various database connections in ASP.NET. It introduces the configuration of MSSQL, Access, Oracle, SQLite, and MySQL databases in detail. It has certain reference value. Those who are interested can learn more. .

1. Database connection statement

1. MSSQL database link example

 <connectionStrings>
 <add name="Conn" connectionString="server=.;database=demo;uid=sa;pwd=123456" providerName="System.Data.SqlClient"/>
 </connectionStrings>

2. Access 2003 database Link example: "{0}" represents the root directory

 <connectionStrings>
 <add name="Conn" connectionString="Provider=Microsoft.Jet.OLEDB.4.0; Data Source={0}App_Data/demo.mdb" providerName="System.Data.OleDb"/>
 </connectionStrings>

Access 2007 or above version link

 <connectionStrings>
 <add name="Conn" connectionString="Provider=Microsoft.Jet.OLEDB.4.0; Data Source={0}App_Data/demo.mdb" providerName="System.Data.OleDb"/>
 </connectionStrings>

3, Oracle database link example

 <connectionStrings>
 <add name="Conn" connectionString="Provider=MSDAORA;Data Source=demo;User ID=sa;Password=123456;" providerName="System.Data.OracleClient"/>
 </connectionStrings>

4, SQLite database link Example

 <connectionStrings>
 <add name="Conn" connectionString="Data Source={0}App_Data/demo.db;failifmissing=false" providerName="System.Data.SQLite"/>
 </connectionStrings>

5: MySQL database link example

 <connectionStrings>
 <add name="Conn" connectionString="host=127.0.0.1;Port=3306;Database=mysql;uid=sa;pwd=12346" providerName="MySql.Data.MySqlClient"/>
 </connectionStrings>

2. json data conversion

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 "{}";
   }
  }

 }
}

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