让C#开发更简单,抽象增删改

　　相信经常做一些MS，CRM 项目的童鞋非常有体会，大部分时间都是在复制和粘贴，大部分项目框架都是建一个三层，首先是DAL建一些增删改查，然后呢是BLL业务层再建一些增删改查，然后UI层再调用增删改查，整个过程非常的繁琐，开发效率并不是很高，这种项目做久了之后，就非常的痛苦，非常的无聊。今天我给大家带来一个抽象出增删改查的框架，相信有些大牛早就总结出来了，不喜勿喷哈，本人旨在分享。

　　你再也不用写增删改查了，我给你抽象出来了！！

　　现在业界火了一种ORM 框架，那就是Dapper，我也是Dapper的粉丝之一，而我总结出来的框架也是基于Daaper。下面是我的代码，首先是Dapper Helper类，数据库通用访问类（用Nuget工具先把Dapper类引用到NetUtility.Dapper.Core项目中去）：

NetUtility.Dapper.Core.DataBaseAccess.cs　　

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Dapper;
using System.Data;
using NetUtility.Entity;
using System.Reflection;

namespace NetUtility.Dapper.Core
{
    /// <summary>
    /// 数据库访问类
    /// </summary>
    public class DataBaseAccess
    {
        public static SqlConnection CreateConnection()
        {
            string connStr = ConfigurationManager.ConnectionStrings["connString"].ConnectionString;
            SqlConnection conn = new SqlConnection(connStr);
            conn.Open();
            return conn;
        }

        /// <summary>
        /// 执行增、删、改方法
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parms"></param>
        /// <returns></returns>
        public static int Execute(string sql, object parms = null)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return conn.Execute(sql,parms);
            }
        }

        /// <summary>
        /// 得到单行单列
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parms"></param>
        /// <returns></returns>
        public static object ExecuteScalar(string sql, object parms = null)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return conn.ExecuteScalar(sql, parms);
            }
        }

        /// <summary>
        /// 单个数据集查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parms"></param>
        /// <returns></returns>
        public static List<TEntity> Query<TEntity>(string sql,Func<TEntity,bool> pre ,object parms = null)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return conn.Query<TEntity>(sql, parms).Where(pre).ToList();
            }
        }

        /// <summary>
        /// 单个数据集查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parms"></param>
        /// <returns></returns>
        public static List<TEntity> Query<TEntity>(string sql, object parms = null)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return conn.Query<TEntity>(sql, parms).ToList();
            }
        }   

        /// <summary>
        /// 多个数据集查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parms"></param>
        /// <returns></returns>
        public static SqlMapper.GridReader MultyQuery(string sql, object parms = null)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return  conn.QueryMultiple(sql, parms);
            }
        }

        /// <summary>
        /// 单个数据集查询
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="parms"></param>
        /// <returns></returns>
        public static TEntity FirstOrDefault<TEntity>(string sql,Func<TEntity,bool> selector, object parms = null)
        {
            using (IDbConnection conn = CreateConnection())
            {
                return conn.Query<TEntity>(sql, parms).Where(selector).FirstOrDefault();
            }
        }
    }
}

我把增删改查抽象出来了，少不了的就是SQL语句的生成，生成SQL语句，要么是映射，要么是反射，而我用的是反射，给一个Entity类，我读取他所有属性和字段，然后生成对应的SQL语句。

NetUtility.Dapper.Core.DataMapping.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace NetUtility.Dapper.Core
{
    internal class DataMapping<TModel> where TModel : class
    {
        #region 数据库类型+DataBaseType
        /// <summary>
        /// 数据库类型
        /// </summary>
        public static string DataBaseType
        {
            get
            {
                string strType = ConfigurationManager.AppSettings["DataBaseType"];
                if (!string.IsNullOrEmpty(strType))
                {
                    return strType;
                }
                else
                {
                    return string.Empty;
                }
            }
        }
        #endregion

        #region 主键属性字段+PrimaryKey
        /// <summary>
        /// 主键字段名称
        /// </summary>
        public static string PrimaryKey
        {
            get
            {
                Type t = typeof(TModel);
                TableInfoAttribute tableInfo = t.GetCustomAttribute(typeof(TableInfoAttribute), true) as TableInfoAttribute;
                if (tableInfo!=null)//如果没有标识表信息特性，则通过表名向数据库中得到主键信息
                {
                    return tableInfo.PrimaryKey;
                }
                else
                {
                    string tableName = TableName();
                    return DataBaseAccess.ExecuteScalar("SELECT name FROM SysColumns WHERE id=Object_Id('" + tableName + "') and colid=(select top 1 colid from sysindexkeys where id=Object_Id('" + tableName + "'))").ToString();
                }
            }
        }
        #endregion

        #region 获取表名+TableName
        /// <summary>
        /// 获取表名
        /// </summary>
        /// <param name="prev">数据库表名前缀</param>
        /// <returns></returns>
        public static string TableName(string prev = "")
        {
            Type t = typeof(TModel);
            TableInfoAttribute tableInfo = t.GetCustomAttribute(typeof(TableInfoAttribute), true) as TableInfoAttribute;
            return tableInfo != null ? tableInfo.TableName : string.Concat(prev, t.Name);
        }
        #endregion

        #region Select 查询语句+GetQuerySql
        /// <summary>
        /// Select 查询语句
        /// </summary>
        /// <returns></returns>
        public static string GetQuerySql()
        {
            StringBuilder sql = new StringBuilder("select * from ");
            sql.Append(TableName());

            return sql.ToString();
        }
        #endregion

        #region Insert非Null属性的对象实例 Sql 语句+GetInsertSql
        /// <summary>
        /// Insert 非Null属性的对象实例 Sql 语句
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public static string GetInsertSql(TModel model)
        {
            StringBuilder sql = new StringBuilder("insert into ");

            string[] props = Propertys(model);
            sql.Append(TableName());
            sql.Append("(");
            sql.Append(string.Join(",", props));
            sql.Append(") values(@");
            sql.Append(string.Join(",@", props));
            sql.Append(");select @@IDENTITY");

            return sql.ToString();
        }
        #endregion

        #region Delete Sql 语句+GetDeleteSql
        /// <summary>
        /// Delete Sql 语句
        /// </summary>
        /// <returns></returns>
        public static string GetDeleteSql()
        {
            return string.Format(@"delete from {0} where {1} in @IdList", TableName(), PrimaryKey);
        }
        #endregion

        #region Update 非Null属性的对象实例 Sql语句+GetUpdateSql
        /// <summary>
        /// Update 非Null属性的对象实例 Sql语句
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public static string GetUpdateSql(TModel model)
        {
            StringBuilder sql = new StringBuilder("update ");
            string[] props = Propertys(model);
            sql.Append(TableName());
            sql.Append(" set ");
            foreach (string propName in props)
            {
                sql.Append(propName + "=@" + propName + ",");
            }
            sql.Remove(sql.Length - , );
            sql.Append(" where " + PrimaryKey + "=@Id");
            return sql.ToString();
        }
        #endregion

        #region 非主键且非Null属性集合+Propertys
        /// <summary>
        /// 非主键且非Null属性
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public static string[] Propertys(TModel model)
        {
            PropertyInfo[] props = typeof(TModel).GetProperties();
            List<string> list = new List<string>();
            string key = PrimaryKey;
            if (props != null && props.Length > )
            {
                foreach (PropertyInfo prop in props)
                {
                    if (prop.GetValue(model, null) != null && !prop.Name.Equals(key, StringComparison.OrdinalIgnoreCase))
                    {
                        list.Add(prop.Name);
                    }
                }
            }

            return list.ToArray();
        }
        #endregion
    }
}

代码中的TableInfoAttribute 类是我建一个属性特性类，用于标识表名和主键名称的特性类，假如Entity实体类上面没有标识主键名称，框架默认会用Entity类名作为表名，建议最好标识一下表名和主键名称。

NetUtility.Dapper.Core.TableInfoAttribute.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace NetUtility.Dapper.Core
{
    [AttributeUsage(AttributeTargets.Class | AttributeTargets.Property, AllowMultiple = true, Inherited = true)]
    /// <summary>
    /// 标识表名、主键等信息特性类
    /// </summary>
    public class TableInfoAttribute : Attribute
    {
        /// <summary>
        /// 数据库表名
        /// </summary>
        public string TableName { get; set; }

        /// <summary>
        /// 主键名称
        /// </summary>
        public string PrimaryKey { get; set; }

        public TableInfoAttribute()
        { }
        public TableInfoAttribute(string tableName, string key)
        {
            this.TableName = tableName;
            this.PrimaryKey = key;
        }
    }
}

好，下面就是新建一个抽象类，用于抽象出增删改查的 ExecuteSql<TModel> 泛型抽象类

　NetUtility.Dapper.Core.ExecuteSql.cs

using Dapper;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace NetUtility.Dapper.Core
{
    public abstract class ExecuteSql<TModel> where TModel : class
    {
        #region Insert非Null属性的对象实例+Insert(TModel model)
        /// <summary>
        /// Insert非Null属性的对象实例
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public virtual int Insert(TModel model)
        {
            string sql = DataMapping<TModel>.GetInsertSql(model);
            object res = DataBaseAccess.ExecuteScalar(sql, model);
            if (res != null)
            {
                return Convert.ToInt32(res);
            }
            return ;
        }
        #endregion

        #region Select * 查询+Query()
        /// <summary>
        /// Select * 查询
        /// </summary>
        /// <returns></returns>
        public virtual List<TModel> Query()
        {
            string sql = DataMapping<TModel>.GetQuerySql();
            return DataBaseAccess.Query<TModel>(sql);
        }
        #endregion

        #region 带查询条件的Select查询+Query(Func<TModel, bool> selector)
        /// <summary>
        /// 带查询条件的Select查询
        /// </summary>
        /// <param name="selector"></param>
        /// <returns></returns>
        public virtual List<TModel> Query(Func<TModel, bool> selector)
        {
            string sql = DataMapping<TModel>.GetQuerySql();
            return DataBaseAccess.Query<TModel>(sql, selector);
        }
        #endregion

        #region  得到一个对象的实例+FirstOrDefault(Func<TModel, bool> selector = null)
        /// <summary>
        /// 得到一个对象的实例
        /// </summary>
        /// <param name="selector"></param>
        /// <returns></returns>
        public virtual TModel FirstOrDefault(Func<TModel, bool> selector = null)
        {
            string sql = DataMapping<TModel>.GetQuerySql();
            return DataBaseAccess.FirstOrDefault<TModel>(sql, selector);
        }
        #endregion

        #region 批量删除+Delete(string[] IdList)
        /// <summary>
        /// 批量删除
        /// </summary>
        /// <param name="IdList"></param>
        /// <returns></returns>
        public virtual int Delete(string[] IdList)
        {
            return DataBaseAccess.Execute(DataMapping<TModel>.GetDeleteSql(), new { IdList = IdList });
        }
        #endregion

        #region Update 一个非Null属性的对象+Update(TModel model)
        /// <summary>
        /// Update 一个非Null属性的对象
        /// </summary>
        /// <param name="model"></param>
        /// <returns></returns>
        public virtual int Update(TModel model)
        {
            return DataBaseAccess.Execute(DataMapping<TModel>.GetUpdateSql(model), model);
        }
        #endregion

        #region 获取多个数据集+MultyQuery(string sql, object param = null)
        /// <summary>
        /// 获取多个数据集
        /// </summary>
        /// <param name="sql"></param>
        /// <param name="param"></param>
        /// <returns></returns>
        public virtual SqlMapper.GridReader MultyQuery(string sql, object param = null)
        {
            return DataBaseAccess.MultyQuery(sql, param);
        }
        #endregion

    }
}

ExecuteSql.cs 类中的方法全是 virsual方法，使用者可以重写他，特别是查询方法，一定会被重写掉。现在NetUtility.Dapper.Core项目中的类全部写完了，现在是我业务类的引用了，我现在只需要建一个业务类继承这个抽象类，这些增删改查方法全都有了，已经不需要写了！

下面是我的两个实体类，实体类用TableInfoAttribute特性类标识出了主键名称和表名称：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NetUtility.Dapper.Core;

namespace NetUtility.Entity
{
    [TableInfo(PrimaryKey ="Id",TableName ="Classes")]
    public class Classes
    {   public int Id { get; set; }
        public string Name { get; set; }
        public string Code { get; set; }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NetUtility.Dapper.Core;

namespace NetUtility.Entity
{
    [TableInfo(PrimaryKey = "Id", TableName = "Student")]
    public class Student
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Code { get; set; }
        public int? Age { get; set; }
        public DateTime? JoinDate { get; set; }
        public int? ClassesId { get; set; }
    }
}

我再新建一个StudentRepertories业务类，继承ExecuteSql抽象类。

NetUtility.Repertories.StudentRepertories.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NetUtility.Dapper.Core;
using NetUtility.Entity;
using NetUtility.Entity.ExstendEntity;//这个是实体类的扩展类，项目中如不需要可移除
using System.Data;
using Dapper;

namespace NetUtility.Repertories
{
    public class StudentRepertories : ExecuteSql<Student>
    {

        public override List<Student> Query()
        {
            return base.Query();
        }

        public  List<StudentInfo> QueryInfo()
        {
            string sql = "select * from Student a left join Classes b on a.ClassesId=b.Id";

            using (IDbConnection conn = DataBaseAccess.CreateConnection())
            {
                return conn.Query<StudentInfo, Classes, StudentInfo>(sql, (stu, classes) => { stu.ClassesModel = classes; return stu; }).ToList();
            }
        }
    }
}

好了，现在我们只需要建一个控制台测试一下有没有问题就是了，亲测，木有问题。

NetUtility.ConsoleItem

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using NetUtility.Repertories;
using NetUtility.Entity;

namespace NetUtility.ConsoleItem
{
    class Program
    {
        static void Main(string[] args)
        {
            //业务对象
             StudentRepertories stu = new StudentRepertories();
            //实体对象
            var model = new Student(){Age = ,ClassesId = ,Code = "",JoinDate = DateTime.Now,Name = "老徐"};
            //新增一个对象
            int StudentId = stu.Insert(model);
            var newModel = stu.FirstOrDefault(a => a.Id == StudentId);
            //Lambda表达式查询
            var list = stu.Query(a => a.Age == );
            //不带参数查询
            var studentInfoList = stu.QueryInfo();
            #region 更新
            newModel.Code = "";
            newModel.Id = StudentId;
            stu.Update(newModel);
            #endregion
          // 删除
            stu.Delete(new string[] { newModel.Id.ToString() });
            Console.ReadKey();
        }
    }
}

各位可以指出我上面的程序一些毛病，相互交流一下，或者有什么更新的做法也可以说说