MVC+EF

html5 • • web开发技术 • 209 阅读

一、MVC+EF

不管是MVC 还是EF 都有文件夹 Controllers 下边的文件必须以Controller 结尾

WEBAPI 接口不要使用中文名称

二、Linq 查询

  • 多表联查

  • Linq 查询

  • 1.简单的linq语法

     

              
              
              
              
              
              
              
     //1
            var ss = from r in db.Am_recProScheme
 select r;
            //2
            var ss1 = db.Am_recProScheme;
            //3
            string sssql = "select * from Am_recProScheme";

     

     

    2.带where的查询

     

     //1
            var ss = from r in db.Am_recProScheme
 where r.rpId > 10
 select r;
            //2
            var ss1 = db.Am_recProScheme.Where(p => p.rpId > 10);
            //3
            string sssql = "select * from Am_recProScheme where rpid>10";

     

     

    3.简单的函数计算（count，min，max，sum）

     

                //1
            ////获取最大的rpId
            //var ss = (from r in db.Am_recProScheme
            //          select r).Max(p => p.rpId);
            ////获取最小的rpId
            //var ss = (from r in db.Am_recProScheme
            //          select r).Min(p => p.rpId);
            //获取结果集的总数
            //var ss = (from r in db.Am_recProScheme                  
            //         select r).Count();
            //获取rpId的和
            var ss = (from r in db.Am_recProScheme
  select r).Sum(p => p.rpId);
?
?
            //2
            //var ss1 = db.Am_recProScheme.Max(p=>p.rpId);
            //var ss1 = db.Am_recProScheme.Min(p => p.rpId);
            //var ss1 = db.Am_recProScheme.Count() ;
            var ss1 = db.Am_recProScheme.Sum(p => p.rpId);
            Response.Write(ss);
?
            //3
            string sssql = "select max(rpId) from Am_recProScheme";
                   sssql = "select min(rpId) from Am_recProScheme";
                   sssql = "select count(1) from Am_recProScheme";
                   sssql = "select sum(rpId) from Am_recProScheme";

     

     

    4.排序order by desc/asc

     

                var ss = from r in db.Am_recProScheme
 where r.rpId > 10
 orderby r.rpId descending  //倒序
 //  orderby r.rpId ascending   //正序
 select r;
?
            //正序
            var ss1 = db.Am_recProScheme.OrderBy(p => p.rpId).Where(p => p.rpId > 10).ToList();
            //倒序
            var ss2 = db.Am_recProScheme.OrderByDescending(p => p.rpId).Where(p => p.rpId > 10).ToList();
?
            string sssql = "select * from Am_recProScheme where rpid>10 order by rpId [desc|asc]";

     

     

    5.top(1)

     

     //如果取最后一个可以按倒叙排列再取值
            var ss = (from r in db.Am_recProScheme 
  select r).FirstOrDefault();
?
            //（）linq to ef 好像不支持 Last() 
            var ss1 = db.Am_recProScheme.FirstOrDefault();
            //var ss1 = db.Am_recProScheme.First();          
?
            string sssql = "select top(1) * from Am_recProScheme";

     

    前面多少条数据取余下的数据

     

     //1
            var ss = (from r in db.Am_recProScheme
  orderby r.rpId descending
  select r).Skip(10); //跳过前10条数据，取10条之后的所有数据   
            //2  
            var ss1 = db.Am_recProScheme.OrderByDescending(p => p.rpId).Skip(10).ToList();
            //3
            string sssql = "select * from  (select ROW_NUMBER()over(order by rpId desc) as rowNum, * from [Am_recProScheme]) as t where rowNum>10";

     

    7.分页数据查询

     

      //1
            var ss = (from r in db.Am_recProScheme
  where r.rpId > 10
  orderby r.rpId descending
  select r).Skip(10).Take(10); //取第11条到第20条数据                   
?
            //2 Take(10): 数据从开始获取，获取指定数量（10）的连续数据
            var ss1 = db.Am_recProScheme.OrderByDescending(p => p.rpId).Where(p => p.rpId > 10).Skip(10).Take(10).ToList();
            //3
            string sssql = "select * from  (select ROW_NUMBER()over(order by rpId desc) as rowNum, * from [Am_recProScheme]) as t where rowNum>10 and rowNum<=20";

     

    8.包含，类似like ‘%%‘

     

      //1
            var ss = from r in db.Am_recProScheme
 where r.SortsText.Contains("张")
 select r;
            //2
            var ss1 = db.Am_recProScheme.Where(p => p.SortsText.Contains("张")).ToList();
            //3
            string sssql = "select * from Am_recProScheme where SortsText like ‘%张%‘";

     

    9.分组group by

     

                //1
            var ss = from r in db.Am_recProScheme
 orderby r.rpId descending
 group r by r.recType into n
 select new
 {
     n.Key,  //这个Key是recType
     rpId = n.Sum(r => r.rpId), //组内rpId之和
     MaxRpId = n.Max(r => r.rpId),//组内最大rpId
     MinRpId = n.Min(r => r.rpId), //组内最小rpId
 };
            foreach (var t in ss)
            {
                Response.Write(t.Key + "--" + t.rpId + "--" + t.MaxRpId + "--" + t.MinRpId);
            }
            //2
            var ss1 = from r in db.Am_recProScheme
 orderby r.rpId descending
 group r by r.recType into n
 select n;
            foreach (var t in ss1)
            {
                Response.Write(t.Key + "--" + t.Min(p => p.rpId));
            }
            //3
            var ss2 = db.Am_recProScheme.GroupBy(p => p.recType);
            foreach (var t in ss2)
            {
                Response.Write(t.Key + "--" + t.Min(p => p.rpId));
            }
            //4
            string sssql = "select recType,min(rpId),max(rpId),sum(rpId) from Am_recProScheme group by recType";           //多字段

     

    var result = (from item in data group item by new { item.Name, item.Type } into items select new { items.Key.Name, items.Key.Type, Cnt = items.Count() }).ToList();

var s = data.GroupBy(p => new { p.Type, p.Name }).Select(p=>new { p.Key.Type, p.Key.Name, cnt=p.Count() }).ToList();

10.连接查询

 

 //1
            var ss = from r in db.Am_recProScheme
 join w in db.Am_Test_Result on r.rpId equals w.rsId
 orderby r.rpId descending
 select r;
            //2
            var ss1 = db.Am_recProScheme.Join(db.Am_Test_Result, p => p.rpId, r => r.rsId, (p, r) => p).OrderByDescending(p => p.rpId).ToList();
            //3
            string sssql = "select r.* from  [Am_recProScheme] as r inner join [dbo].[Am_Test_Result] as t on r.[rpId] = t.[rsId] order by r.[rpId] desc";

 

11.sql中的In

            //1
            var ss = from p in db.Am_recProScheme
          where (new int?[] { 24, 25,26 }).Contains(p.rpId)
          select p;
            foreach (var p in ss)
            {
                Response.Write(p.Sorts);
            }
            //2
            string st = "select * from Am_recProScheme where rpId in(24,25,26)";

 

  • 匿名类型return Json(new {totalcount,totalpage,list });

三、Postman使用

四、MVC访问API

  • WEBAPI 配置 跨域 （CORS）

跨域请求:将文件复制到API项目中的Web.config文件中 在</handlers>下插入此段代码

 技术分享图片

 

 

 

跨域设置:将文件复制到API项目中的Global.asax文件中,在WebApiApplication方法中插入此段代码

 技术分享图片

 

MVC+EF

[db:回答]

以上是MVC+EF的全部内容。
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