一、安装EFCode包
EFCore需要根据不同的数据库选择不同的数据库提供程序database provider，各数据库的包地址：https://docs.microsoft.com/zh-cn/ef/core/providers/
使用sqlserver数据库使用的是Microsoft.EntityFrameworkCore.SqlServer包，支持SQL Server 2008 及以上版本
Microsoft.EntityFrameworkCore.SqlServer包依赖Microsoft.EntityFrameworkCore 和Microsoft.EntityFrameworkCore.Relational两个包
新建Core2 Web Application (Model-View-Controller)项目，Microsoft.EntityFrameworkCore.SqlServer 已经默认安装到了 Microsoft.AspNetCore.All元包里面，不需要再次安装
二、建立实体并添加EF上下文
给每个实体创建一个DbSet属性，每一个Dbset相当于数据库的一张表，每一个实体相当于数据库的一行
public class EFDbContext : DbContext ???{ ???????public EFDbContext(DbContextOptions<EFDbContext> options) : base(options) ???????{ ???????} ???????public DbSet<Admin> Admins { get; set; } ???????public DbSet<Company> Companies { get; set; }｝可以重写DbContext的OnModelCreating来指定实体对应的数据库表名，默认数据库使用实体的复数做为表名
protected override void OnModelCreating(ModelBuilder modelBuilder) ???????{ ???????????modelBuilder.Entity<Admins>().ToTable("Admin"); ????????}三、在DI注册EF上下文，Startup.cs文件里面的ConfigureServices方法里面注册EF上下文
public class Startup ???{ ???????public Startup(IConfiguration configuration) ???????{ ???????????Configuration = configuration; ???????} ???????public IConfiguration Configuration { get; } ???????// This method gets called by the runtime. Use this method to add services to the container. ???????public void ConfigureServices(IServiceCollection services) ???????{ ???????????????????????services.AddDbContext<EFDbContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection"))); ???????????services.AddMvc().AddJsonOptions(option => ???????????{ ???????????????option.SerializerSettings.ContractResolver = new Newtonsoft.Json.Serialization.DefaultContractResolver(); ???????????} ???????????); ???????}数据库连接配置在appsettings.json文件里面：
"ConnectionStrings": { ???"DefaultConnection": "Data Source=.\\SQLExpress;Initial Catalog=DbTest;User ID=sa;Password=sa" ?},DI会在创建控制器时，通过构造函数注入EF上下文，
public class AdminsController : SysBaseController ???{ ???????private readonly EFDbContext _context; ???????public AdminsController(EFDbContext context) ???????{ ???????????_context = context; ???????}｝
在ASP.NET Core 2.0 web项目中使用EntityFrameworkCore
原文地址：https://www.cnblogs.com/tangchun/p/8758851.html