asp.net用sql数据库生成json字符串并显示出来
use Shop create table DictBase(Id int identity(1,1) primary key,Name nchar(10))
insert into DictBase select '包装' UNION ALL select '价格' UNION ALL select '品牌'
工厂方法模式
IDAL层（添加一个IDictBase接口，在里面定义一个方法）
using System; using System.Collections.Generic; using System.Data; namespace Letao.IDAL { /// <summary> /// 接口：类别字典键 /// </summary> public interface IDictBase { #region 获取 /// <summary> /// 获取所有字典键名 /// </summary> List<Model.DictBase> Get(); #endregion } }
DALFactory层（DataAccess新建接口实现工厂模式CreateDictBase）
using System; using System.Reflection; using System.Configuration; using Letao.IDAL; namespace Letao.DALFactory { /// <summary> /// 工厂反射层 /// </summary> public sealed class DataAccess { private static readonly string AssemblyPath = ConfigurationManager.AppSettings["SQLServerDAL"]; /// <summary> /// 类别字典键名 /// </summary> public static Letao.IDAL.IDictBase CreateDictBase() { string ClassNamespace = AssemblyPath + ".DictBase"; return (IDictBase)Assembly.Load(AssemblyPath).CreateInstance(ClassNamespace); } } }
SQLServerDAL层（在项目中添加类DictBase，继承自接口IDictBase，实现的方法是向控制台输出所有字典键名）
using System; using System.Data; using System.Data.SqlClient; using System.Collections.Generic; namespace Letao.SQLServerDAL { /// <summary> /// 类别字典键 /// </summary> class DictBase:IDAL.IDictBase { #region 获取 /// <summary> /// 获取所有字典键名 /// </summary> public List<Model.DictBase> Get() { string sql = string.Format("select * from DictBase"); List<Model.DictBase> list = new List<Model.DictBase>(); using(SqlDataReader dr=DBUtility.DbHelperSQL.ExecuteReader(ConnString.connReadonly,CommandType.Text,sql,null)) { while(dr.Read()) { Model.DictBase model = new Model.DictBase(); object obj; obj = dr["Id"]; if(obj!=null &&obj!=DBNull.Value) { model .Id =(int )obj; } model.Name = dr["Name"].ToString(); list.Add(model ); } } return list; } } }
BLL层（创建一个DictBase的工厂类，使它继承自CreateDictBase接口，创建一个方法，使它的返回值为IDictBase，最后在方法的实现里面返回实例化的DictBase）
using System; using System.Collections.Generic; namespace Letao.BLL { /// <summary> /// 类别字典键 /// </summary> public class DictBase { protected static Letao.IDAL.IDictBase dal =Letao .DALFactory .DataAccess.CreateDictBase(); /// <summary> /// 获取所有字典键名 /// </summary> public static List<Model.DictBase> Get() { return dal.Get(); } } }
Model层（DictBase类）
using System; namespace Letao.Model { /// <summary> /// 类别字典键 /// </summary> public class DictBase { /// <summary> /// 字典健名编号 /// </summary> public int Id { get; set; } /// <summary> /// 字典关键字 /// </summary> public string Name{ get; set; } } }
备注：
DBUtility层（DbHelperSQL类、ConnString类）
using System; using System.Data; using System.Data.SqlClient; namespace Letao.DBUtility { public class DbHelperSQL { /// <summary> /// 返回数据内容（SqlDataReader） /// </summary> /// <param name="connectionString">数据库连接字符串</param> /// <param name="cmdType">执行类型（过程/语句）</param> /// <param name="cmdText">执行的过程名称/查询语句</param> /// <param name="commandParameters">command执行的SqlParameter[]数组</param> /// <returns>SqlDataReader 返回执行后的数据内容</returns> public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); SqlConnection conn = new SqlConnection(connectionString); try { PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection); cmd.Parameters.Clear(); return rdr; } catch { //Close(conn); //Dispose(conn); throw; } } } }
using System; namespace Letao.SQLServerDAL { /// <summary> /// 数据库连接字符串 /// </summary> class ConnString { /// <summary> /// 读写数据库连接字符串 /// </summary> public static string conn { get { if (_conn == null) { _conn = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionStringWrite"].ToString(); } return _conn; } } private static string _conn = null; /// <summary> /// 只读数据库连接字符串 /// </summary> public static string connReadonly { get { if (_connReadonly == null) { _connReadonly = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionStringReadonly"].ToString(); } return _connReadonly; } } private static string _connReadonly = null; } }
接下来添加App.config文件，来实现系统所选择的数据库是什么数据库
<?xml version="1.0"?> <appSettings> <add key="title" value="乐淘"/> <add key="SQLServerDAL" value ="Letao.SQLServerDAL"/> </appSettings>
页面
<html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title></title> <script src="/Admin/Scripts/jquery-1.8.3.min.js" type="text/javascript"></script> </head> <body> <div> <ul id="dictbase"></ul> </div> <script type="text/javascript"> $(function () { $.getJSON('test.aspx?action=get', function (json) { var _html = []; for (var key in json) { _html.push('<li data="' + json[key].Id + '">' + json[key].Name + '</li>'); } $("#dictbase").empty().append(_html.join('')); }); }) </script> </body> </html>
protected void Page_Load(object sender, EventArgs e) { if (Request.Headers["X-Requested-With"] != null && Request.Headers["X-Requested-With"].ToLower() == "XMLHttpRequest".ToLower()) { Response.Clear(); Response.ContentType = "application/json"; if (Request["action"] == "get") Response.Write(GetJson()); Response.End(); } } protected string GetJson() { System.Web.Script.Serialization.JavaScriptSerializer json = new System.Web.Script.Serialization.JavaScriptSerializer(); List<Letao.Model.DictBase> list = new List<Letao.Model.DictBase>(); list = Letao.BLL.DictBase.Get(); return json.Serialize(list); }
效果
知识点：
1、从数据库转换成json字符串
2、X-Requested-With是否是第一次加载
谷歌浏览器审查元素后的结果
参考网址：1、ASP.NET用SQL Server中的数据来生成JSON字符串
http://www.cnblogs.com/jacksonwj/archive/2008/08/10/1264525.html
2、asp.net 简单工厂模式和工厂方法模式之论述
http://www.jb51.net/article/29212.htm
