MVC Link连接数据库增删改查方法的不同写法

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;



namespace MvcApplication5注册验证.Models

{

    public class ZhuceBF

    {

        private mydboDataContext _Context = new mydboDataContext();

        public List<zhuce> Select()

        {

            return _Context.zhuce.ToList();

        }

        public zhuce Selectbyid(string id)

        {

            var query = _Context.zhuce.Where(p=>p.ID==id);

            if (query.Count()>0)

            {

                return query.First();

            }

            return null;

        }

        public void Insert(string id,string username,string userpwd)

        {

            if (username == "" || username == " ")

            {

            }

            else

            {

                zhuce data = new zhuce();

                data.ID = id;

                data.Username = username;

                data.Userpwd = userpwd;

                _Context.zhuce.InsertOnSubmit(data);

                _Context.SubmitChanges();

            }

        }



        public void Update(string id, string username, string userpwd)

        {

            var query = _Context.zhuce.Where(p=>p.ID==id);

            if (query.Count()>0)

            {

                zhuce data = query.First();

                data.ID = id;

                data.Username = username;

                data.Userpwd = userpwd;

            }

            _Context.SubmitChanges();

        }



        public void Delete(string id)

        {

            var query = _Context.zhuce.Where(p=>p.ID==id);

            if (query.Count()>0)

            {

                zhuce data = query.First();

                _Context.zhuce.DeleteOnSubmit(data);

                _Context.SubmitChanges();

            }

        }

        //简写方法

        public void Insert( zhuce data)

        {

            _Context.zhuce.InsertOnSubmit(data);

            _Context.SubmitChanges();

        }

        public void Updata(zhuce data)

        {

           // zhuce sdata = _Context.zhuce.Where(p=>p.ID==data.ID).First();

            //上面这一局查询一堆选择第一条

            //下面这一局是查询一条，结果一样

           zhuce sdata = _Context.zhuce.Single(p=>p.ID ==data.ID);



           sdata.ID = data.ID;

           sdata.Username = data.Username;

           sdata.Userpwd = data.Userpwd;

        }

        //删除多条数据

        public void Delete(string name)

        {

            List<zhuce> list= _Context.zhuce.Where(p => p.Username == name).ToList();

          

                _Context.zhuce.DeleteAllOnSubmit(list);

                _Context.SubmitChanges();

        }

        //模糊查询

        public List<zhuce> SelectByname(string name)

        {

            return _Context.zhuce.Where(r=>r.Username.Contains(name)).ToList();

        }



        //表达式查询

        public List<zhuce> Selectbyname(string name)

        {

            //query相当于一条数据，_Context,zhuce相当于List<zhuce>

            var a=from query1 in _Context.zhuce where query1.Username.Contains(name) select query1;

            return a.ToList();

        }

    }

}