dapper 操作类封装

 using System;
 using System.Collections.Generic;
 using System.Data;
 using System.Data.SQLite;
 using System.Linq;
 using System.Text;
 using Dapper;
 using PaiXie.Utils;
 namespace PaiXie.Pos.Client.Core
 {
     public class Data<T> where T : class
     {
         #region 构造函数

         private static Data<T> _instance;
         public static Data<T> GetInstance()
         {
             if (_instance == null)
             {
                 _instance = new Data<T>();
             }
             return _instance;
         }

         #endregion

         /// <summary>
         /// 分页列表
         /// </summary>
         /// <param name="data"></param>
         /// <param name="model"></param>
         /// <param name="count"></param>
         /// <param name="context"></param>
         /// <param name="transaction"></param>
         /// <returns></returns>
         public List<T> GetQueryManyForPage(SelectBuilder data, T model, out int count, SQLiteConnection context = null, IDbTransaction transaction = null)
         {
             if (context == null) context = Db.GetInstance().Context();
             string sqlStr = Db.GetInstance().GetSqlForSelectBuilder(data);
             string sqlStrCount = Db.GetInstance().GetSqlForTotalBuilder(data);
             List<T> list = context.Query<T>(sqlStr, model, transaction).ToList();
             count = ZConvert.StrToInt(context.ExecuteScalar(sqlStrCount, model, transaction), );
             return list;
         }
         /// <summary>
         /// 添加
         /// </summary>
         /// <param name="query"></param>
         /// <param name="model"></param>
         /// <param name="context"></param>
         /// <param name="transaction"></param>
         /// <returns></returns>
         public int Add(string query, T model, SQLiteConnection context = null, IDbTransaction transaction = null)
         {
             if (context == null) context = Db.GetInstance().Context();
             //  query += " ; select last_insert_rowid() newid";
             //  string id = context.ExecuteScalar(query, model, transaction).ToString();
             //  return ZConvert.StrToInt(id, 0);
             int id = context.Execute(query, model, transaction);
             return id;
         }

         /// <summary>
         /// 修改
         /// </summary>
         /// <param name="query"></param>
         /// <param name="model"></param>
         /// <param name="context"></param>
         /// <param name="transaction"></param>
         /// <returns></returns>
         public int Update(string query, T model, SQLiteConnection context = null, IDbTransaction transaction = null)
         {
             if (context == null) context = Db.GetInstance().Context();
             int id = context.Execute(query, model, transaction);
             return id;
         }
         /// <summary>
         /// 删除
         /// </summary>
         /// <param name="tablename"></param>
         /// <param name="wheresql"></param>
         /// <param name="model"></param>
         /// <param name="context"></param>
         /// <param name="transaction"></param>
         /// <returns></returns>
         public int Delete(string tablename, string wheresql, T model, SQLiteConnection context = null, IDbTransaction transaction = null)
         {
             if (context == null) context = Db.GetInstance().Context();
             string query = "DELETE FROM  " + tablename + "  WHERE " + wheresql;
             int id = context.Execute(query, model, transaction);
             return id;
         }
         /// <summary>
         /// 获取单个实体
         /// </summary>
         /// <param name="tablename"></param>
         /// <param name="wheresql"></param>
         /// <param name="model"></param>
         /// <param name="context"></param>
         /// <param name="transaction"></param>
         /// <returns></returns>
         public T GetModel(string tablename, string wheresql, T model, SQLiteConnection context = null, IDbTransaction transaction = null)
         {
             if (context == null) context = Db.GetInstance().Context();
             string query = "SELECT  * FROM " + tablename + " WHERE " + wheresql + "  LIMIT 0,1";
             T obj = context.Query<T>(query, model, transaction).SingleOrDefault();
             return obj;
         }

         /// <summary>
         /// 实体列表
         /// </summary>
         /// <param name="query"></param>
         /// <param name="model"></param>
         /// <param name="context"></param>
         /// <param name="transaction"></param>
         /// <returns></returns>
         public List<T> GetModelList(string query, T model, SQLiteConnection context = null, IDbTransaction transaction = null)
         {
             if (context == null) context = Db.GetInstance().Context();
             List<T> list = context.Query<T>(query, model, transaction).ToList();
             return list;
         }

     }
 }

 using System;
 using System.Collections.Generic;
 using System.Data.SQLite;
 using System.Linq;
 using System.Text;
 using  Dapper;
 using System.Windows.Forms;
 namespace PaiXie.Pos.Client.Core {
     public class Db {

         #region 构造函数

         private static Db _instance;
         public static Db GetInstance() {
             if (_instance == null) {
                 _instance = new Db();
             }
             return _instance;
         }

         #endregion

         #region Context
         public SQLiteConnection Context() {
             SQLiteConnectionStringBuilder sb = new SQLiteConnectionStringBuilder();
             sb.DataSource =
                 @"//10.0.0.105/db/DB.s3db";
             // Application.StartupPath + @"\Data.dll";//DB.db3
             SQLiteConnection con = new SQLiteConnection(sb.ToString());
             return con;
         }
         #endregion

         #region 分页语句拼接
         public string GetSqlForSelectBuilder(SelectBuilder data) {
             var sql = "";
             sql = "select " + data.Select;
             sql += " from " + data.From;
             if (data.WhereSql.Length > )
                 sql += " where " + data.WhereSql;
             if (data.GroupBy.Length > )
                 sql += " group by " + data.GroupBy;
             if (data.Having.Length > )
                 sql += " having " + data.Having;
             if (data.OrderBy.Length > )
                 sql += " order by " + data.OrderBy;
             if (data.PagingItemsPerPage >
                 && data.PagingCurrentPage >
                 ) {
                     sql += string.Format(" limit {0} offset {1}", data.PagingItemsPerPage, ((data.PagingCurrentPage * data.PagingItemsPerPage) - data.PagingItemsPerPage + ) - );
             }
             return sql;
         }
         public string GetSqlForTotalBuilder(SelectBuilder data) {
             var sql = "";
             sql = "select count(*)";
             sql += " from " + data.From;
             if (data.WhereSql.Length > )
                 sql += " where " + data.WhereSql;
             return sql;
         }
         #endregion

     }

     #region SelectBuilder
     public class SelectBuilder {
         public int PagingCurrentPage { get; set; }
         public int PagingItemsPerPage { get; set; }

         private string _Having = "";
         public string Having {
             set { _Having = value; }
             get { return _Having; }
         }

         private string _GroupBy = "";
         public string GroupBy {
             set { _GroupBy = value; }
             get { return _GroupBy; }
         }

         private string _OrderBy = "";
         public string OrderBy {
             set { _OrderBy = value; }
             get { return _OrderBy; }
         }

         private string _From = "";
         public string From {
             set { _From = value; }
             get { return _From; }
         }

         private string _Select="";
         public string Select {
             set { _Select = value; }
             get { return _Select; }
         }

         private string _WhereSql="";
         public string WhereSql {
             set { _WhereSql = value; }
             get { return _WhereSql; }
         }

     }
     #endregion
 }