public class Startup

    {

        // This method gets called by the runtime. Use this method to add services to the container.

        // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940

        public void ConfigureServices(IServiceCollection services)

        {

            services.AddMvc();   //注册mvc服务

        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.

        public void Configure(IApplicationBuilder app, IHostingEnvironment env)

        {

            if (env.IsDevelopment())

            {

                app.UseDeveloperExceptionPage();

            }

            app.UseMvc(routes=> {     //开启mvc

                routes.MapRoute(

                    name:"default",

                    template:"{controller=Home}/{action=Index}/{id?}"

                    );

            });

        }

    }

{

  "Logging": {

    "LogLevel": {

      "Default": "Warning"

    }

  },

  "DBSetting": {

    "ConnectString": "server=.;database=test_core;uid=sa;pwd=123"

  },

  "AllowedHosts": "*"

}

 public class BaseHelper

    {

        public SqlSugarClient db;

        static IConfiguration configure = new ConfigurationBuilder().SetBasePath(Directory.GetCurrentDirectory())

            .AddJsonFile("appsettings.json").Build();

        private static readonly string _connectionstring = configure["DBSetting:ConnectString"];

       // public BaseHelper(string connectionString)

        public BaseHelper()

        {

             db = new SqlSugarClient(

                    new ConnectionConfig()

                    {

                        ConnectionString = _connectionstring,

                        DbType = DbType.SqlServer,//设置数据库类型

                        IsAutoCloseConnection = true,//自动释放数据务，如果存在事务，在事务结束后释放

                        InitKeyType = InitKeyType.Attribute //从实体特性中读取主键自增列信息

                    });

            //用来打印Sql方便你调式

            db.Aop.OnLogExecuting = (sql, pars) =>

                            {

                                Console.WriteLine(sql + "\r\n" +

                                db.Utilities.SerializeObject(pars.ToDictionary(it => it.ParameterName, it => it.Value)));

                                Console.WriteLine();

                            };

        }

        public SqlSugarClient GetDb()

        {

            return db;

        }

        public bool InsertInto<T>(T obj) where T : class, new()

        {

            return db.Insertable(obj).ExecuteCommandIdentityIntoEntity();

        }

        public int UpdateInfo<T>(Expression<Func<T, bool>> set, Expression<Func<T, bool>> where) where T : class, new()

        {

            return db.Updateable<T>().SetColumns(set).Where(where).ExecuteCommand();

        }

    }

 public class HomeController : Controller

    {

        private static  SqlSugarClient _db = new BaseHelper().GetDb();

        private SimpleClient<Student> db = new SimpleClient<Student>(_db);

        public IActionResult Index()

        {

            //db.Insert(new Student()

            //{

            //    ClassId = 113,

            //    Name = "小明"

            //});

            //_db.Insertable(new Student()  {ClassId = 1,Name = "小高"}).ExecuteCommandIdentityIntoEntity();

            //var re = _db.Updateable(new Student() { ClassId=2, Name = "小梅" }).Where(p=>p.ClassId==2).ExecuteCommand();   //更新全部

            //_db.Updateable<Student>().SetColumns(p=>p.Name=="小小").Where(p => p.ClassId == 2).ExecuteCommand();   //更新指定字段

            //_db.Deleteable<Student>().Where(p => p.Name == "2").ExecuteCommand(); //删除

            UpdateInfo<Student>(p=>p.Name=="大大",p=>p.ClassId==);

            new BaseHelper().InsertInto<Student>(new Student()

            {

                ClassId = ,

                Name = "小明"

            });

            return View();

        }

        public bool InsertInto<T>(T obj) where T : class, new()

        {

            return _db.Insertable(obj).ExecuteCommandIdentityIntoEntity();

        }

        public int UpdateInfo<T>(Expression<Func<T, bool>> set, Expression<Func<T, bool>> where) where T : class, new()

        {

            return _db.Updateable<T>().SetColumns(set).Where(where).ExecuteCommand();

        }

    }