.NET Core1.1+VS2017RC+MySQL+EF搭建多层Web应用程序

先贴上解决方案截图

一、新建4个解决方案文件夹

1-Presentation

2-Application

3-Domain

4-Infrastructure

二、在解决方案文件夹中分别创建项目

其余项目创建省略

项目引用关系：

1.ContosoUniversity.WebAdmin引用ContosoUniversity.Application、ContosoUniversity.Domain

2.ContosoUniversity.Application引用ContosoUniversity.Repository、ContosoUniversity.Domain

3.ContosoUniversity.Repository引用ContosoUniversity.Domain

4.ContosoUniversity.Domain不引用任何项目

三、ContosoUniversity.Domain项目中添加dll Microsoft.EntityFrameworkCore、Microsoft.EntityFrameworkCore.Relational

四、ContosoUniversity.Domain项目添加Student、SchoolContext、DbInitializer类

Student：POCO对象，对应数据库中的Student表

SchoolContext：数据库上下文，用于数据库CRUD以及Migrations操作

DbInitializer：初始化数据库并添加测试数据

using System;

namespace ContosoUniversity.Domain
{
    public class Student
    {
        public int ID { get; set; }
        public string LastName { get; set; }
        public string FirstMidName { get; set; }
        public DateTime EnrollmentDate { get; set; }
    }
}

using Microsoft.EntityFrameworkCore;

namespace ContosoUniversity.Domain.Data
{
    public class SchoolContext : DbContext
    {
        public SchoolContext(DbContextOptions<SchoolContext> options) : base(options)
        {
        }

        public DbSet<Student> Students { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<Student>().ToTable("Student");
        }
    }
}

using System;
using System.Linq;

namespace ContosoUniversity.Domain.Data
{
    public static class DbInitializer
    {
        public static void Initialize(SchoolContext context)
        {
            context.Database.EnsureCreated();

            // Look for any students.
            if (context.Students.Any())
            {
                return;   // DB has been seeded
            }

            var students = new Student[]
            {
            new Student{FirstMidName="Carson",LastName="Alexander",EnrollmentDate=DateTime.Parse("2005-09-01")},
            new Student{FirstMidName="Meredith",LastName="Alonso",EnrollmentDate=DateTime.Parse("2002-09-01")},
            new Student{FirstMidName="Arturo",LastName="Anand",EnrollmentDate=DateTime.Parse("2003-09-01")},
            new Student{FirstMidName="Gytis",LastName="Barzdukas",EnrollmentDate=DateTime.Parse("2002-09-01")},
            new Student{FirstMidName="Yan",LastName="Li",EnrollmentDate=DateTime.Parse("2002-09-01")},
            new Student{FirstMidName="Peggy",LastName="Justice",EnrollmentDate=DateTime.Parse("2001-09-01")},
            new Student{FirstMidName="Laura",LastName="Norman",EnrollmentDate=DateTime.Parse("2003-09-01")},
            new Student{FirstMidName="Nino",LastName="Olivetto",EnrollmentDate=DateTime.Parse("2005-09-01")}
            };
            foreach (Student s in students)
            {
                context.Students.Add(s);
            }
            context.SaveChanges();
        }
    }
}

五、ContosoUniversity.WebAdmin项目修改

1.appsetting.json文件添加MySQL连接字符串

 "ConnectionStrings": {
    "DefaultConnection": "server=xxx;user id=xxx;password=xxx;database=ContosoUniversity;"
  }

2.添加NuGet包MySql.Data.EntityFrameworkCore 6.10.0-alpha、Microsoft.EntityFrameworkCore.Tools 1.1.0-preview4-final

打开工程.csproj工程文件，添加CliTool“Microsoft.EntityFrameworkCore.Tools.DotNet”

否则在migrations操作时会报【No executable found matching command "dotnet-ef"】错误

MySql版本不要选7.0.6-IR31，项目跑起来会报"MySql.Data.EntityFrameworkCore.Storage.Internal.MySQLCommandBuilderFactory..ctor(ISensitiveDataLogger<RelationalCommandBuilderFactory> logger, DiagnosticSource diagnosticSource, IRelationalTypeMapper typeMapper)"错误

3.StartUp类ConfigureServices方法注入数据库上下文

      public void ConfigureServices(IServiceCollection services)
        {
            services.AddDbContext<SchoolContext>(options =>
                options.UseMySQL(Configuration.GetConnectionString("DefaultConnection"), b => b.MigrationsAssembly("ContosoUniversity.WebAdmin")));

            // Add framework services.
            services.AddMvc();
        }

注意，标红的代码不可缺少，否则EntityFramework无法执行Migrations，报错信息如下

4.StartUp添加数据库初始化

改造Configure方法签名，添加SchoolContext参数

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, SchoolContext context)

Configure方法末尾添加数据库初始化代码

DbInitializer.Initialize(context);

最后

把其余各层的代码都加上项目就可以跑起来了，通过Migrations操作维护开发库，.NET Core+MySQL+EF使用VS2017RC构建项目的坑基本就是这些了。。

注意

NuGet包Install或Uninstall命名执行后，查看VS2017RC中依赖的NuGet包发现没有变化（实际上已Install或Uninstall，VS2017RC没有刷新），此时需要关闭解决方案重新打开，这时NuGet依赖才会刷新，这时VS2017RC的一个BUG！