（1）==数据库配置文件  <!--数据库配置-->  <appSettings>    <!--SQLite-->    <add key="SQLString" value=http://www.mamicode.com/"~\App_Data\OldDemo.db"/>    <add key="SQLString2" value=http://www.mamicode.com/"|DataDirectory|OldDemo.db"/>  </appSettings>（2）配置类class Config    {        public static string DatabaseFile = "";        public static string DataSource        {            get            {                return string.Format("data source={0}", ConfigurationManager.AppSettings["SQLString2"]);            }        }    }（3）==BaseServices类using System;using System.Collections.Generic;using System.Data;using System.Data.SQLite;using System.Linq;using System.Runtime.Remoting.Messaging;using System.Text;using App.Core.Constant;using PetaPoco;namespace App.Core.Service{    public abstract class BaseService    {        private IDbConnection connection;        public BaseService()        {            connection = new SQLiteConnection(Config.DataSource);        }        /// <summary>        /// 查询所有对象        /// </summary>        /// <typeparam name="T">泛型对象</typeparam>        /// <returns></returns>        public List<T> Query<T>()        {            var list = new List<T>();            try            {                string className = typeof(T).ToString();                var db = new Database(connection);                string name = className.Substring(                    className.LastIndexOf(‘.‘) + 1,                    className.Length - className.LastIndexOf(‘.‘) - 1);                connection.Open();                list = db.Fetch<T>(string.Format("select * from {0} ", name));            }            catch (Exception ex)            {                throw ex;            }            return list;        }        /// <summary>        /// 删除对象        /// </summary>        /// <typeparam name="T">泛型对象</typeparam>        /// <param name="objData"></param>        /// <returns></returns>        public int Delete<T>(object objData)        {            var result = 0;            try            {                var db = new Database(connection);                connection.Open();                result = db.Delete<T>(objData);            }            catch (Exception ex)            {                throw ex;            }            return result;        }        /// <summary>        /// 添加一条记录        /// </summary>        /// <typeparam name="T"></typeparam>        /// <param name="objData"></param>        /// <returns></returns>        public T Add<T>(object objData)        {            T result;            try            {                var db = new Database(connection);                connection.Open();                result = (T)Convert.ChangeType(db.Insert(objData), typeof(T));            }            catch (Exception ex)            {                throw ex;            }            return result;        }    }}