abp-vnext-ZeroToOne系列

前言
1.初步构建项目架构
2.Authors领域

前言

本系列参照官方文档BookStore,创建一个BookStore应用程序。

旨在从零开始(ZeroToOne, zto)不使用模板，

从创建一个空的解决方案开始，一步一步地去了解如何使用Abp.vNext去构建一个应用程序。

1.初步构建项目架构

创建一个空的解决方案Zto.BookStore,然后依次添加如下项目，

注意：以下创建的项目，都的以Zto.BookStore.为前缀，为了叙述的简单，故省略之，比如：

*.Domain指的是项目Zto.BookStore.Domain

模块化架构最佳实践 & 约定

应用程序启动模板

1.1 *.Domain.Shared

基本设置

修改默认命名空间为Zto.BookStore
新建文件Localization

依赖包

Volo.Abp.Core

知识点: Abp模块化

参考资料：

Abp-Notes:模块化

创建`AbpModule`

根目录下创建AbpModule:

using Volo.Abp.Modularity;

namespace Zto.BookStore
{
    public class BookStoreDomainSharedModule : AbpModule
    {
    }
}

创建`BookType`

创建文件夹Books,在该文件夹下新建BookType.cs:

namespace Zto.BookStore.Books
{
    public enum BookType
    {
        Undefined, //未定义的
        Adventure, //冒险
        Biography, //传记
        Dystopia,  //地狱
        Fantastic, //神奇的
        Horror,    //恐怖,
        Science,   //科学
        ScienceFiction, //科幻小说
        Poetry     //诗歌
    }
}

Book相关常量

在Books文件夹下新建一个BookConsts.cs类，用于存储Book相关常量值

namespace Zto.BookStore.Books
{
    public static class BookConsts
    {
        public const int MaxNameLength = 256; //名字最大长度
    }
}

本地化

官方文档

创建本地化资源

开始的UI开发之前,我们首先要准备本地化的文本(这是通常在开发应用程序时需要做的).

本地化资源用于将相关的本地化字符串组合在一起,并将它们与应用程序的其他本地化字符串分开，

通常一个模块会定义自己的本地化资源. 本地化资源就是一个普通的类. 例如:

在文件夹Localization下，新建BookStoreResource.cs类

    [LocalizationResourceName("BookStore")]
    public class BookStoreResource
    {

    }

[LocalizationResourceName("BookStore")]标记资源名

在文件夹Localization/BookStore，添加两个语言资源json文件，

en.json

{
  "Culture": "en",
  "Texts": {
    "Menu:Home": "Home",
    "Welcome": "Welcome",
    "LongWelcomeMessage": "Welcome to the application. This is a startup project based on the ABP framework. For more information, visit abp.io.",
    "Menu:BookStore": "Book Store",
    "Menu:Books": "Books",
    "Actions": "Actions",
    "Edit": "Edit",
    "PublishDate": "Publish date",
    "NewBook": "New book",
    "Name": "Name",
    "Type": "Type",
    "Price": "Price",
    "CreationTime": "Creation time",
    "AreYouSureToDelete": "Are you sure you want to delete this item?",
    "Enum:BookType:0": "Undefined",
    "Enum:BookType:1": "Adventure",
    "Enum:BookType:2": "Biography",
    "Enum:BookType:3": "Dystopia",
    "Enum:BookType:4": "Fantastic",
    "Enum:BookType:5": "Horror",
    "Enum:BookType:6": "Science",
    "Enum:BookType:7": "Science fiction",
    "Enum:BookType:8": "Poetry",
    "BookDeletionConfirmationMessage": "Are you sure to delete the book '{0}'?",
    "SuccessfullyDeleted": "Successfully deleted!",
    "Permission:BookStore": "Book Store",
    "Permission:Books": "Book Management",
    "Permission:Books.Create": "Creating new books",
    "Permission:Books.Edit": "Editing the books",
    "Permission:Books.Delete": "Deleting the books",
    "BookStore:00001": "There is already an author with the same name: {name}",
    "Permission:Authors": "Author Management",
    "Permission:Authors.Create": "Creating new authors",
    "Permission:Authors.Edit": "Editing the authors",
    "Permission:Authors.Delete": "Deleting the authors",
    "Menu:Authors": "Authors",
    "Authors": "Authors",
    "AuthorDeletionConfirmationMessage": "Are you sure to delete the author '{0}'?",
    "BirthDate": "Birth date",
    "NewAuthor": "New author"
  }
}

zh-Hans.json

{
  "culture": "zh-Hans",
  "texts": {
    "Menu:Home": "首页",
    "Welcome": "欢迎",
    "LongWelcomeMessage": "欢迎来到该应用程序. 这是一个基于ABP框架的启动项目. 有关更多信息, 请访问 abp.io.",

    "Enum:BookType:0": "未知",
    "Enum:BookType:1": "冒险",
    "Enum:BookType:2": "传记",
    "Enum:BookType:3": "地狱",
    "Enum:BookType:4": "神奇的",
    "Enum:BookType:5": "恐怖",
    "Enum:BookType:6": "科学",
    "Enum:BookType:7": "科幻小说 ",
    "Enum:BookType:8": "诗歌"
  }
}

每个本地化文件都需要定义 culture (文化) 代码 (例如 "en" 或 "en-US").
texts 部分只包含本地化字符串的键值集合 (键也可能有空格).

特别注意：

必须将语言资源文件的属性设置为

复制到输出目录：不复制
生成操作：嵌入的资源

1.2 *.Domain

基本设置

修改默认命名空间为Zto.BookStore

项目引用

*.Domain.Shared

依赖包

Volo.Abp.Core

创建`AbpModule`

根目录下创建AbpModule:

using Volo.Abp.Modularity;

namespace Zto.BookStore
{
    [DependsOn(typeof(BookStoreDomainSharedModule))]
    public class BookStoreDomainModule : AbpModule
    {
    }
}

创建`Book`领域模型

创建文件夹Books,在该文件夹下新建Book.cs

using Volo.Abp.Domain.Entities.Auditing;
using System;

namespace Zto.BookStore.Books
{
    public class Book : AuditedAggregateRoot<Guid>
    {
        public Guid AuthorId { get; set; }
        public String Name { get; set; }
        public BookType Type { get; set; }
        public DateTime PublishDate { get; set; }
        public float Price { get; set; }
    }
}

项目常量值类`BookStoreConsts`

在根目录下创建BookStoreConsts.cs,用于保存项目中常量数据值

namespace Zto.BookStore
{
    public static class BookStoreConsts
    {
        public const string DbTablePrefix = "Bks"; //常量值:表前缀
        public const string DbSchema = null; //常量值:表的架构
    }
}

1.3 *.EntityFrameworkCore

修改默认命名空间为Zto.BookStore
创建文件夹EntityFrameworkCore

项目引用

*.Domain

依赖包

Volo.Abp.EntityFrameworkCore
Volo.Abp.EntityFrameworkCore.SqlServer:使用MsSqlServer数据库

创建`AbpModule`

在文件夹EntityFrameworkCore下创建AbpModule:

using Volo.Abp.Modularity;

namespace Zto.BookStore.EntityFrameworkCore
{
    [DependsOn(typeof(BookStoreDomainModule))]
    public class BookStoreEntityFrameworkCoreModule : AbpModule
    {
        public override void ConfigureServices(ServiceConfigurationContext context)
        {
            context.Services.AddAbpDbContext<BookStoreDbContext>(options =>
            {
                /* Remove "includeAllEntities: true" to create
                 * default repositories only for aggregate roots */
                options.AddDefaultRepositories(includeAllEntities: true);
            });

            Configure<AbpDbContextOptions>(options =>
            {
                /* The main point to change your DBMS.
                 * See also BookStoreMigrationsDbContextFactory for EF Core tooling. */
                options.UseSqlServer();
            });
        }
    }
}

代码解析：

AddDefaultRepositories(includeAllEntities: true)

添加默认Repository实现，includeAllEntities: true表示为所以实体类实现仓储(Repository)类
options.UseSqlServer();使用MsSqlServer数据库

创建`DbContext`

在文件夹EntityFrameworkCore中创建BookStoreDbContext.cs

using Microsoft.EntityFrameworkCore;
using Volo.Abp.Data;
using Volo.Abp.EntityFrameworkCore;
using Zto.BookStore.Books;

namespace Zto.BookStore.EntityFrameworkCore
{
    [ConnectionStringName("BookStoreConnString")]
    public class BookStoreDbContext : AbpDbContext<BookStoreDbContext>
    {
        public DbSet<Book> Books { get; set; }
        public BookStoreDbContext(DbContextOptions<BookStoreDbContext> options)
            : base(options)
        {
        }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);
            
            /* Configure the shared tables (with included modules) here */
            // 配置从其它modules引入的模型


            /* Configure your own tables/entities inside the ConfigureBookStore method */
            // 配置本项目自己的表和实体模型
            builder.ConfigureBookStore();
        }
    }
}

代码解析：

[ConnectionStringName("BookStoreConnString")]：表示要使用的数据库连接字符串

BookStore的EFcore 实体模型映射

创建/EntityFrameworkCore/BookStoreDbContextModelCreatingExtensions.cs:

该类用于配置本项目（即：BookStore项目）自己的表和实体模型

using Microsoft.EntityFrameworkCore;
using Volo.Abp.EntityFrameworkCore.Modeling;
using Zto.BookStore.Books;

namespace Zto.BookStore.EntityFrameworkCore
{
    public static class BookStoreDbContextModelCreatingExtensions
    {
        public static void ConfigureBookStore(this ModelBuilder builder)
        {
            Check.NotNull(builder, nameof(builder));

            /* Configure your own tables/entities inside here */
            builder.Entity<Book>(e =>
            {
                e.ToTable(BookStoreConsts.DbTablePrefix + "Books", BookStoreConsts.DbSchema);
                e.ConfigureByConvention(); //auto configure for the base class props ,优雅的配置和映射继承的属性,应始终对你所有的实体使用它.
                e.Property(p => p.Name).HasMaxLength(BookConsts.MaxNameLength);

            });
        }
    }
}

其中：

e.ToTable(BookStoreConsts.DbTablePrefix + "Books", BookStoreConsts.DbSchema);

配置表的前缀和表的架构

e.ConfigureByConvention();优雅的配置和映射继承的属性,应始终对你所有的实体使用它

命令行中执行数据库迁移

如果严格按上述顺序依次创建项目，并添加代码

这时，我们可以随便创建一个控制台程序，并添加配置文件appsettings.json

{
  "ConnectionStrings": {
    "BookStoreConnString": "Server=.;Database=BookStore_Zto;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

设置控制台程序为默认启动项目，
打开程【序包管理器控制台】，并将【默认项目】设置为项目：.EntityFrameworkCore.DbMigrations ,
执行EF数据库迁移命令

add-migration initDb

会抛出如下错误：

Unable to create an object of type 'BookStoreDbContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728

这是因为：我们没有为BookStoreDbContext提供无参数构造函数，但是``BookStoreDbContext必须得继承 AbpDbContext,其不提供无参数构造函数，故在项目*.EntityFrameworkCore.DbMigrations中是无法执行数据库迁移的，如何解决数据库迁移呢？请看章节【**设计时创建DbContext`**】。

1.4 *.EntityFrameworkCore.DbMigrations

Q1:为什么要创建这个工程呢?

**A: **用于EF的数据库迁移，因为如果项目是使用其它的 O/R框架，迁移的方式就不一样，所以数据库的迁移，也使用接口方式，这样就可以替换。

基本设置

修改默认命名空间为Zto.BookStore
创建文件夹EntityFrameworkCore

项目引用

*.EntityFrameworkCore

依赖包

Microsoft.EntityFrameworkCore.Design:设计时创建DbContex,用于命令行执行数据库迁移

创建`AbpModule`

在文件夹EntityFrameworkCore下创建AbpModule:

using Volo.Abp.Modularity;

namespace Zto.BookStore.EntityFrameworkCore
{
    [DependsOn(
        typeof(BookStoreEntityFrameworkCoreModule)
        )]
    public class BookStoreEntityFrameworkCoreDbMigrationsModule : AbpModule
    {
        context.Services.AddAbpDbContext<BookStoreMigrationsDbContext>();
    }
}

迁移`DbContexnt`

在文件夹EntityFrameworkCore下创建BookStoreMigrationsDbContext.cs，

此DbContext仅仅用于数据库迁移

using Microsoft.EntityFrameworkCore;
using Volo.Abp.EntityFrameworkCore;

namespace Zto.BookStore.EntityFrameworkCore
{
    /// <summary>
    /// This DbContext is only used for database migrations.
    /// It is not used on runtime. See BookStoreDbContext for the runtime DbContext.
    /// It is a unified model that includes configuration for
    /// all used modules and your application.
    /// 
    /// 这个DbContext只用于数据库迁移。
    /// 它不在运行时使用。有关运行时DbContext，请参阅BookStoreDbContext。
    /// 它是一个统一配置所有使用的模块和您的应用程序的模型
    /// </summary>
    [ConnectionStringName("BookStoreConnString")]
    public class BookStoreMigrationsDbContext : AbpDbContext<BookStoreMigrationsDbContext>
    {
        public BookStoreMigrationsDbContext(DbContextOptions<BookStoreMigrationsDbContext> options)
            : base(options)
        {
            
        }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);

            /* Configure the shared tables (with included modules) here */
            // 配置从其它modules引入的模型



            /* Configure your own tables/entities inside the ConfigureBookStore method */
            // 配置本项目自己的表和实体模型
            builder.ConfigureBookStore();
        }

    }
}

注意：在此处我们就通过特性[ConnectionStringName("BookStoreConnString")]指定其连接字符串

设计时创建`DbContext`

在章节【 *.EntityFrameworkCore -- > 命令行中执行数据库迁移】中，看到那时使用ef命令是执行数据库迁移的时，会抛出如下异常：

Unable to create an object of type 'BookStoreDbContext'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728

解决方案就是设计时创建DbContext。

什么是设计时创建`DbContext`

参考资料：
https://docs.microsoft.com/zh-cn/ef/core/cli/dbcontext-creation?tabs=dotnet-core-cli

从设计时工厂创建DbContext：
你还可以通过实现接口来告诉工具如何创建 DbContext IDesignTimeDbContextFactory<TContext> ：
如果实现此接口的类在与派生的项目相同的项目中 DbContext
或在应用程序的启动项目中找到，
则这些工具将绕过创建 DbContext 的其他方法，并改用设计时工厂。

如果需要以不同于运行时的方式配置 DbContext 的设计时，则设计时工厂特别有用 DbContext 。如果构造函数采用其他参数，
但未在 di 中注册，如果根本不使用 di，
或者出于某种原因而不是使用 CreateHostBuilder ASP.NET Core 应用程序的类中的方法 Main 。

总之一句话：
实现了IDesignTimeDbContextFactory<BookStoreMigrationsDbContext>，
就可以使用命令行执行数据库迁移，例如：

(1).在 NET Core CLI中执行： dotnet ef database update
(2).在 Visual Studio中执行：Update-Database

实现`IDesignTimeDbContextFactory<>`

综上，

确保已入如下Nuget包：
- Microsoft.EntityFrameworkCore.Design
- Volo.Abp.EntityFrameworkCore.SqlServer
  
  如果使用的是MySql数据库，已入的包是Volo.Abp.EntityFrameworkCore.MySQL
在文件夹EntityFrameworkCore下创建BookStoreMigrationsDbContextFactory,

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.Extensions.Configuration;
using System.IO;

namespace Zto.BookStore.EntityFrameworkCore
{
    /// <summary>
    ///   This class is needed for EF Core console commands
    ///   (like Add-Migration and Update-Database commands) 
    ///   
    ///   参考资料：
    ///   https://docs.microsoft.com/zh-cn/ef/core/cli/dbcontext-creation?tabs=dotnet-core-cli
    ///   从设计时工厂创建DbContext：
    ///   你还可以通过实现接口来告诉工具如何创建 DbContext IDesignTimeDbContextFactory<TContext> ：
    ///   如果实现此接口的类在与派生的项目相同的项目中 DbContext 
    ///   或在应用程序的启动项目中找到，
    ///   则这些工具将绕过创建 DbContext 的其他方法，并改用设计时工厂。
    /// 
    ///   如果需要以不同于运行时的方式配置 DbContext 的设计时，则设计时工厂特别有用 DbContext 。如果构造函数采用其他参数，
    ///   但未在 di 中注册，如果根本不使用 di，
    ///   或者出于某种原因而不是使用 CreateHostBuilder ASP.NET Core 应用程序的类中的方法 Main 。
    /// 
    /// 
    ///   总之一句话：
    ///   实现了IDesignTimeDbContextFactory<BookStoreMigrationsDbContext>，
    ///   就可以使用命令行执行数据库迁移,
    ///      (1).在 NET Core CLI中执行： dotnet ef database update
    ///      (2).在 Visual Studio中执行：Update-Database 
    /// </summary>
    public class BookStoreMigrationsDbContextFactory : IDesignTimeDbContextFactory<BookStoreMigrationsDbContext>
    {
        public BookStoreMigrationsDbContext CreateDbContext(string[] args)
        {
            var configuration = BuildConfiguration();
            var builder = new DbContextOptionsBuilder<BookStoreMigrationsDbContext>()
                 .UseSqlServer(configuration.GetConnectionString("BookStoreConnString")); //SqlServer数据库
                //.UseMySql(configuration.GetConnectionString("BookStoreConnString"), ServerVersion.); //MySql数据库

            return new BookStoreMigrationsDbContext(builder.Options);
        }

        private static IConfigurationRoot BuildConfiguration()
        {
            var builder = new ConfigurationBuilder()
                //项目Zto.BookStore.DbMigrator的根目录
                .SetBasePath(Path.Combine(Directory.GetCurrentDirectory(), "../Zto.BookStore.DbMigrator/"))
                .AddJsonFile("appsettings.json", optional: false);

            return builder.Build();

            return builder.Build();
        }
    }
}

这样就可以在NET Core CLI或Visual Studio中使用命令诸如如下命令执行数据库迁移

Add-Migration
dotnet ef database update

ef命名会自动找到类BookStoreMigrationsDbContextFactory

public class BookStoreMigrationsDbContextFactory : IDesignTimeDbContextFactory<BookStoreMigrationsDbContext>

这时，我们可以随便创建一个控制台程序（本例为项目Zto.BookStore.DbMigrator），并添加配置文件appsettings.json

{
  "ConnectionStrings": {
    "BookStoreConnString": "Server=.;Database=BookStore_Zto;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

设置控制台程序为默认启动项目，

不过，如果现在已经通过以下代码在BookStoreMigrationsDbContextFactory中明确指明了配置文件的地址：

        private static IConfigurationRoot BuildConfiguration()
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(Path.Combine(Directory.GetCurrentDirectory(), "../Zto.BookStore.DbMigrator/"))
                .AddJsonFile("appsettings.json", optional: false);

            return builder.Build();
        }

即，如下代码

  .SetBasePath(Path.Combine(Directory.GetCurrentDirectory(), "../Zto.BookStore.DbMigrator/"))

指明了配置文件位于项目Zto.BookStore.DbMigrator的根目中，所以这时可以不用将设置控制台程序为默认启动项目

打开程【程序包管理器控制台】，并将【默认项目】设置为项目：*.EntityFrameworkCore.DbMigrations ,

执行EF数据库迁移命令

add-migration initDb

这时，命令行提示：

PM> add-migration initDb
Build started...
Build succeeded.
To undo this action, use Remove-Migration.

把挂起的migration更新到数据库

update-database

这时，命令行提示：

PM> update-database
Build started...
Build succeeded.
Security Warning: The negotiated TLS 1.0 is an insecure protocol and is supported for backward compatibility only. The recommended protocol version is TLS 1.2 and later.
Security Warning: The negotiated TLS 1.0 is an insecure protocol and is supported for backward compatibility only. The recommended protocol version is TLS 1.2 and later.
Security Warning: The negotiated TLS 1.0 is an insecure protocol and is supported for backward compatibility only. The recommended protocol version is TLS 1.2 and later.
Applying migration '20201207183001_initDb'.
Done.
PM>

同时在项目.EntityFrameworkCore.DbMigrations的根目录下,会自动生成文件夹Migrations,其中包含两个文件

20201207183001_initDb.cs

using System;
using Microsoft.EntityFrameworkCore.Migrations;

namespace Zto.BookStore.Migrations
{
    public partial class initDb : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateTable(
                name: "BksBooks",
                columns: table => new
                {
                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
                    AuthorId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
                    Name = table.Column<string>(type: "nvarchar(256)", maxLength: 256, nullable: true),
                    Type = table.Column<int>(type: "int", nullable: false),
                    PublishDate = table.Column<DateTime>(type: "datetime2", nullable: false),
                    Price = table.Column<float>(type: "real", nullable: false),
                    ExtraProperties = table.Column<string>(type: "nvarchar(max)", nullable: true),
                    ConcurrencyStamp = table.Column<string>(type: "nvarchar(40)", maxLength: 40, nullable: true),
                    CreationTime = table.Column<DateTime>(type: "datetime2", nullable: false),
                    CreatorId = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
                    LastModificationTime = table.Column<DateTime>(type: "datetime2", nullable: true),
                    LastModifierId = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_BksBooks", x => x.Id);
                });
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropTable(
                name: "BksBooks");
        }
    }
}

BookStoreMigrationsDbContextModelSnapshot.cs：迁移快照

数据库也自动生成了数据库及其相关表

在项目`*.EntityFrameworkCore.DbMigrations`中数据库迁移的局限性

直接在项目*.EntityFrameworkCore.DbMigrations中使用命令行执行数据库迁移有如下局限性：

不能支持多租户(如果开发的系统要求支持多租户的话)的数据库迁移
不能执行种子数据：

使用EF Core执行标准的 Update-Database 命令,但是它不会初始化种子数据.

鉴于以上局限性，我们把数据库迁移的工作全部集中到控制台项目.DbMigrator中，以下两节所创建的类

EntityFrameworkCoreBookStoreDbSchemaMigrator
BookStoreDbMigrationService

就是为了这个目标而提前准备的。

迁移接口：IBookStoreDbSchemaMigrator

在项目*.Domain的/Data文件夹下，创建接口：IBookStoreDbSchemaMigrator，如下所示：

public interface IBookStoreDbSchemaMigrator
{
    Task MigrateAsync();
}

创建其实现类EntityFrameworkCoreBookStoreDbSchemaMigrator，主要是通过代码

dbContext.database.MigrateAsync();

更新migration到数据库：

using System.Threading.Tasks;
using Volo.Abp.DependencyInjection;
using Zto.BookStore.Data;

namespace Zto.BookStore.EntityFrameworkCore
{
    public class EntityFrameworkCoreBookStoreDbSchemaMigrator : IBookStoreDbSchemaMigrator, ITransientDependency
    {
        private readonly IServiceProvider _serviceProvider;

        public EntityFrameworkCoreBookStoreDbSchemaMigrator(IServiceProvider serviceProvider)
        {
            _serviceProvider = serviceProvider;
        }

        public async Task MigrationAsync()
        {
            /*
            * 我们有意从IServiceProvider解析BookStoreMigrationsDbContext(而不是直接注入它)，
            * 是为了能正确获取当前的范围、当前租户的连接字符串
            */
            var dbContext = _serviceProvider.GetRequiredService<BookStoreMigrationsDbContext>();
            var database = dbContext.Database;
            //var connString = database.GetConnectionString();

            /*
             * Asynchronously applies any pending migrations for the context to the database.
             * Will create the database if it does not already exist.
             */
            await database.MigrateAsync();
        }
    }
}

特别注意：

database.MigrateAsync();只是相当于update-database`，故：在该方法执行前，

确保已经手动执行命令add-migration xxx创建migration

数据库迁移服务

创建一个数据库迁移服务BookStoreDbMigrationService,使用代码（而不是EFCore命令行）统一管理所有数据库迁移任务，比如：

调用实现了上节所定义的接口IBookStoreDbSchemaMigrator的实现类，
若系统执行多租户，为租户执行数据库迁移
执行种子数

其中，关键性代码如下：

更新migration到数据库
```
await database.MigrateAsync();
```
执行种子数据
```
 _dataSeeder.SeedAsync(tenant?.Id);
```

完整代码如下：

BookStoreDbMigrationService.cs

using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Volo.Abp.Data;
using Volo.Abp.DependencyInjection;
using Volo.Abp.MultiTenancy;
using Volo.Abp.TenantManagement;

namespace Zto.BookStore.Data
{
    public class BookStoreDbMigrationService : ITransientDependency
    {
        public ILogger<BookStoreDbMigrationService> Logger { get; set; }

        private readonly IDataSeeder _dataSeeder;
        private readonly IEnumerable<IBookStoreDbSchemaMigrator> _dbSchemaMigrators;
        private readonly ITenantRepository _tenantRepository;
        private readonly ICurrentTenant _currentTenant;

        public BookStoreDbMigrationService(
            IDataSeeder dataSeeder,
            IEnumerable<IBookStoreDbSchemaMigrator> dbSchemaMigrators,
            ITenantRepository tenantRepository,
            ICurrentTenant currentTenant)
        {
            _dataSeeder = dataSeeder;
            _dbSchemaMigrators = dbSchemaMigrators;
            _tenantRepository = tenantRepository;
            _currentTenant = currentTenant;

            Logger = NullLogger<BookStoreDbMigrationService>.Instance;
        }

        public async Task MigrateAsync()
        {
            Logger.LogInformation("Started database migrations...");

            await MigrateDatabaseSchemaAsync(); //执行数据库迁移
            await SeedDataAsync();  //执行种子数据
            Logger.LogInformation($"Successfully completed host database migrations.");

            /*-----------------------------------------------------------------
             * 以下为多租户执行的数据库迁移
             -----------------------------------------------------------------*/
            var tenants = await _tenantRepository.GetListAsync(includeDetails: true);
            var migratedDatabaseSchemas = new HashSet<string>();
            foreach (var tenant in tenants)
            {
                if (!tenant.ConnectionStrings.Any())
                {
                    continue;
                }

                using (_currentTenant.Change(tenant.Id))
                {
                    var tenantConnectionStrings = tenant.ConnectionStrings
                        .Select(x => x.Value)
                        .ToList();

                    if (!migratedDatabaseSchemas.IsSupersetOf(tenantConnectionStrings))
                    {
                        await MigrateDatabaseSchemaAsync(tenant);

                        migratedDatabaseSchemas.AddIfNotContains(tenantConnectionStrings);
                    }

                    await SeedDataAsync(tenant);
                }

                Logger.LogInformation($"Successfully completed {tenant.Name} tenant database migrations.");
            }

            Logger.LogInformation("Successfully completed database migrations.");
        }

        /// <summary>
        /// 执行数据库迁移
        /// </summary>
        /// <param name="tenant"></param>
        /// <returns></returns>
        private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
        {
            Logger.LogInformation(
                $"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");

            foreach (var migrator in _dbSchemaMigrators)
            {
                await migrator.MigrateAsync();
            }
        }

        /// <summary>
        /// 执行种子数据
        /// </summary>
        /// <param name="tenant"></param>
        /// <returns></returns>
        private async Task SeedDataAsync(Tenant tenant = null)
        {
            Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");

            await _dataSeeder.SeedAsync(tenant?.Id);
        }
    }
}

代码解析：

MigrateDatabaseSchemaAsync()循环执行所有数据库迁移接口实例
SeedDataAsync()执行种子数据
MigrateAsync()方法将被下一节的创建的迁移控制台程序项目.DbMigrator使用，用于统一执行数据库迁移操作

注意：

因为这里我们使用到了多租户数据库迁移的判定，需要额外已入以下包：

Volo.Abp.TenantManagement.Domain

简化`BookStoreDbMigrationService`

由于目前缺乏对

多租户
IDataSeeder

的了解，所以把跟它们相关的功能代码注释掉，简化后的``BookStoreDbMigrationService`如下:

using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Logging.Abstractions;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Volo.Abp.Data;
using Volo.Abp.DependencyInjection;
using Volo.Abp.MultiTenancy;
using Volo.Abp.TenantManagement;

namespace Zto.BookStore.Data
{
    public class BookStoreDbMigrationService : ITransientDependency
    {
        public ILogger<BookStoreDbMigrationService> Logger { get; set; }
        
        private readonly IEnumerable<IBookStoreDbSchemaMigrator> _dbSchemaMigrators;

        public BookStoreDbMigrationService(
            IEnumerable<IBookStoreDbSchemaMigrator> dbSchemaMigrators)
        {
            _dbSchemaMigrators = dbSchemaMigrators;
            Logger = NullLogger<BookStoreDbMigrationService>.Instance;
        }

        public async Task MigrateAsync()
        {
            Logger.LogInformation("Started database migrations...");
            await MigrateDatabaseSchemaAsync(); //执行数据库迁移
            Logger.LogInformation("Successfully completed database migrations.");
        }

        /// <summary>
        /// 执行数据库迁移
        /// </summary>
        /// <param name="tenant"></param>
        /// <returns></returns>
        private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
        {
            Logger.LogInformation(
                $"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");

            foreach (var migrator in _dbSchemaMigrators)
            {
                await migrator.MigrateAsync();
            }
        }

    }
}

1.5 *.DbMigrator

新建控制台项目*.DbMigrator，以后所有的数据库迁移都推荐使这个控制台项目进行，

可以在开发和生产环境迁移数据库架构和初始化种子数据.

基本设置

创建配置文件appsettings.json:

{
  "ConnectionStrings": {
    "BookStoreConnString": "Server=.;Database=BookStore_Zto;Trusted_Connection=True;MultipleActiveResultSets=true"
  }
}

特别注意：

一定要把配置文件的属性设置为：

复制到输出目录：始终复制
生成操作：内容

项目引用

*.EntityFrameworkCore.DbMigrations

依赖包

Microsoft.EntityFrameworkCore.Tools：数据库迁移
Volo.Abp.Autofac：依赖注入
Serilog日志：
- Serilog.Sinks.File
- Serilog.Sinks.Console
- Serilog.Extensions.Logging
Microsoft.Extensions.Hosting:控制台宿主程序

创建`AbpModule`

在根目录下创建AbpModule:

using Volo.Abp.Autofac;
using Zto.BookStore.EntityFrameworkCore;
using Volo.Abp.Modularity;

namespace Zto.BookStore.DbMigrator
{
    [DependsOn(
        typeof(AbpAutofacModule),
        typeof(BookStoreEntityFrameworkCoreDbMigrationsModule)
        )]
    public class BookStoreDbMigratorModule : AbpModule
    {
    }
}

创建`HostServer`

知识点：IHostedService

当注册 IHostedService 时，.NET Core 会在应用程序启动和停止期间分别调用 IHostedService 类型的 StartAsync() 和 StopAsync() 方法。

此外，如果我们想控制我们自己的服务程序的生命周期，那么可以使用IHostApplicationLifetime

IHostSerice定义如下：


namespace Microsoft.Extensions.Hosting
{
    //
    // 摘要:
    //     Defines methods for objects that are managed by the host.
    public interface IHostedService
    {
        Task StartAsync(CancellationToken cancellationToken);
        Task StopAsync(CancellationToken cancellationToken);
    }
}

数据库迁移`HostedService`

创建一个名为DbMigratorHostedService的类，继承IHostedService接口

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Serilog;
using System.Threading;
using System.Threading.Tasks;
using Volo.Abp;
using Zto.BookStore.Data;

namespace Zto.BookStore.DbMigrator
{
    public class DbMigratorHostedService : IHostedService
    {
        //自己控制的服务程序的生命周期
        private readonly IHostApplicationLifetime _hostApplicationLifetime;

        public DbMigratorHostedService(IHostApplicationLifetime hostApplicationLifetime)
        {
            _hostApplicationLifetime = hostApplicationLifetime;
        }
        public async Task StartAsync(CancellationToken cancellationToken)
        {
            using (var application = AbpApplicationFactory.Create<BookStoreDbMigratorModule>(options =>
            {
                options.UseAutofac();
                options.Services.AddLogging(c => c.AddSerilog());
            }))
            {
                application.Initialize();

                await application
                    .ServiceProvider
                    .GetRequiredService<BookStoreDbMigrationService>()
                    .MigrateAsync();

                application.Shutdown();

                _hostApplicationLifetime.StopApplication();
            }
        }

        public Task StopAsync(CancellationToken cancellationToken)
        {
            return Task.CompletedTask;
        }
    }
}

其中，核心代码只是：

BookStoreDbMigrationService.MigrateAsync()

执行数据库的迁移，包括：更新migration和种子数据

依赖注入`HostedService`

知识点：Serilog

在控制台项目中使用Serilog

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Serilog;
using Serilog.Events;
using System.IO;
using System.Threading.Tasks;

namespace Zto.BookStore.DbMigrator
{
    class Program
    {
        static async Task Main(string[] args)
        {
            Log.Logger = new LoggerConfiguration()
                .MinimumLevel.Information() //设置最低等级
                .MinimumLevel.Override("Microsoft", LogEventLevel.Warning) //根据命名空间或类型重置日志最小级别
                .MinimumLevel.Override("Volo.Abp", LogEventLevel.Warning)
#if DEBUG
                .MinimumLevel.Override("Zto.BookStore", LogEventLevel.Debug)
#else
                .MinimumLevel.Override("Zto.BookStore", LogEventLevel.Information)
#endif
                .Enrich.FromLogContext()
                .WriteTo.File(Path.Combine(Directory.GetCurrentDirectory(), "Logs/logs.txt")) //将日志写到文件
                .WriteTo.Console()//将日志写到控制台
                .CreateLogger();

            await CreateHostBuilder(args).RunConsoleAsync();
        }

        public static IHostBuilder CreateHostBuilder(string[] args) => 
            Host.CreateDefaultBuilder(args)
                .ConfigureLogging((context, logging) => logging.ClearProviders()) //Removes all logger providers from builder.
                .ConfigureServices((hostContext, services) =>
        {
            services.AddHostedService<DbMigratorHostedService>();
        });
    }
}

代码解析：

依赖注入DbMigratorHostedService服务，控制台程序自动将执行HostService的StartAsync()方法

执行数据库迁移

设置控制台程序为启动项目，并运行，执行数据库迁移。

控制台输出日志：

[13:54:12 INF] Started database migrations...
[13:54:12 INF] Migrating schema for host database...
Security Warning: The negotiated TLS 1.0 is an insecure protocol and is supported for backward compatibility only. The recommended protocol version is TLS 1.2 and later.
[13:54:14 INF] Successfully completed host database migrations.

执行完成后，自动生成数据库及其相关表：

特别注意：

这个控制台程序最终的本质是执行dbContext.database.MigrateAsync();只是相当于update-database，

故：在该方法执行前，确保在项目*.EntityFrameworkCore.DbMigrations中已经手动执行命令add-migration xxx创建migration

种子数据

在运行应用程序之前最好将初始数据添加到数据库中. 本节介绍ABP框架的数据种子系统. 如果你不想创建种子数据可以跳过本节,但是建议你遵循它来学习这个有用的ABP Framework功能。

`IDataSeedContributor`:种子数贡献者

在 *.Domain 项目下创建派生 IDataSeedContributor 的类,并且拷贝以下代码:

using System;
using System.Threading.Tasks;
using Volo.Abp.Data;
using Volo.Abp.DependencyInjection;
using Volo.Abp.Domain.Repositories;
using Zto.BookStore.Books;

namespace Zto.BookStore
{
    public class BookStoreDataSeederContributor
      : IDataSeedContributor, ITransientDependency
    {
        private readonly IRepository<Book, Guid> _bookRepository;

        public BookStoreDataSeederContributor(IRepository<Book, Guid> bookRepository)
        {
            _bookRepository = bookRepository;
        }

        public async Task SeedAsync(DataSeedContext context)
        {
            if (await _bookRepository.GetCountAsync() <= 0)
            {
                await _bookRepository.InsertAsync(
                    new Book
                    {
                        Name = "1984",
                        Type = BookType.Dystopia,
                        PublishDate = new DateTime(1949, 6, 8),
                        Price = 19.84f
                    },
                    autoSave: true
                );

                await _bookRepository.InsertAsync(
                    new Book
                    {
                        Name = "The Hitchhiker's Guide to the Galaxy",
                        Type = BookType.ScienceFiction,
                        PublishDate = new DateTime(1995, 9, 27),
                        Price = 42.0f
                    },
                    autoSave: true
                );
            }
        }
    }
}

如果数据库中当前没有图书,则此代码使用 IRepository<Book, Guid>(默认为repository)将两本书插入数据库

其中，IDataSeedContributor接口如下:

namespace Volo.Abp.Data
{
    public interface IDataSeedContributor
    {
        Task SeedAsync(DataSeedContext context);
    }
}

IDataSeedContributor 定义了 SeedAsync 方法用于执行 数据种子逻辑.
通常检查数据库是否已经存在种子数据.
你可以注入服务,检查数据播种所需的任何逻辑.

`IDataSeeder`服务:执行种子数据

数据种子贡献者由ABP框架自动发现,并作为数据播种过程的一部分执行.

如何自动执行种子数据呢？答案是：IDataSeeder服务

你可以通过依赖注入 IDataSeeder 并且在你需要时使用它初始化种子数据. 它内部调用 IDataSeedContributor 的实现去完成数据播种

修改项目 *.Domain中的BookStoreDbMigrationService，依赖注入

 private readonly IDataSeeder _dataSeeder;

并如下使用执行种子数据

 await _dataSeeder.SeedAsync(tenant?.Id);

下面是修改后的完整代码如下：

public class BookStoreDbMigrationService : ITransientDependency
    {
        public ILogger<BookStoreDbMigrationService> Logger { get; set; }

        private readonly IDataSeeder _dataSeeder;
        private readonly IEnumerable<IBookStoreDbSchemaMigrator> _dbSchemaMigrators;

        public BookStoreDbMigrationService(
            IDataSeeder dataSeeder,
            IEnumerable<IBookStoreDbSchemaMigrator> dbSchemaMigrators
            )
        {
            _dataSeeder = dataSeeder;
            _dbSchemaMigrators = dbSchemaMigrators;

            Logger = NullLogger<BookStoreDbMigrationService>.Instance;
        }

        public async Task MigrateAsync()
        {
            Logger.LogInformation("Started database migrations...");

            await MigrateDatabaseSchemaAsync(); //执行数据库迁移
            await SeedDataAsync();  //执行种子数据

            Logger.LogInformation("Successfully completed database migrations.");
        }

        /// <summary>
        /// 执行数据库迁移
        /// </summary>
        /// <param name="tenant"></param>
        /// <returns></returns>
        private async Task MigrateDatabaseSchemaAsync(Tenant tenant = null)
        {
            Logger.LogInformation(
                $"Migrating schema for {(tenant == null ? "host" : tenant.Name + " tenant")} database...");

            foreach (var migrator in _dbSchemaMigrators)
            {
                await migrator.MigrateAsync();
            }
        }

        /// <summary>
        /// 执行种子数据
        /// </summary>
        /// <param name = "tenant" ></ param >
        /// < returns ></ returns >
        private async Task SeedDataAsync(Tenant tenant = null)
        {
            Logger.LogInformation($"Executing {(tenant == null ? "host" : tenant.Name + " tenant")} database seed...");
            await _dataSeeder.SeedAsync(tenant?.Id);

        }
    }

设置控制台程序*.DbMigrator为启动项目，并运行，执行数据库迁移。

这时查看Book表,多了两条种子数据：

dataSeeder.SeedAsync(tenant?.Id)干了啥？

_dataSeeder是个什么呢？

1.6 *.Application.Contracts

应用服务层

应用服务实现应用程序的用例, 将领域层逻辑公开给表示层.

从表示层(可选)调用应用服务,DTO (数据传对象) 作为参数. 返回(可选)DTO给表示层.

基本设置

修改默认命名空间为Zto.BookStore
创建文件夹Books

项目引用

*.Domain.Shared

依赖包

*.Volo.Abp.Ddd.Application.Contracts

创建`AbpModule`

在文件夹Books下创建AbpModule:

using Volo.Abp.Modularity;

namespace Zto.BookStore
{
    [DependsOn(
     typeof(BookStoreDomainSharedModule)
        )]
    public class BookStoreApplicationContractsModule : AbpModule
    {

    }
}

DTO

在文件夹Books下创建Dto:

`BooksDto`

using System;
using Volo.Abp.Application.Dtos;

namespace Zto.BookStore.Books
{
    public class BookDto : AuditedEntityDto<Guid>
    {
        public Guid AuthorId { get; set; }

        public string AuthorName { get; set; }

        public string Name { get; set; }

        public BookType Type { get; set; }

        public DateTime PublishDate { get; set; }

        public float Price { get; set; }
    }
}

DTO类被用来在 表示层 和 应用层 传递数据.查看DTO文档查看更多信息.
为了在页面上展示书籍信息,BookDto被用来将书籍数据传递到表示层.
BookDto继承自 AuditedEntityDto<Guid>.跟上面定义的 Book 实体一样具有一些审计属性.

`CreateUpdateBookDto`

using System;
using System.ComponentModel.DataAnnotations;


namespace Zto.BookStore.Books
{
    public class CreateUpdateBookDto
    {
        public Guid AuthorId { get; set; }

        [Required]
        [StringLength(BookConsts.MaxNameLength)]
        public string Name { get; set; }

        [Required]
        public BookType Type { get; set; } = BookType.Undefined;

        [Required]
        [DataType(DataType.Date)]
        public DateTime PublishDate { get; set; } = DateTime.Now;

        [Required]
        public float Price { get; set; }
    }
}

这个DTO类被用于在创建或更新书籍的时候从用户界面获取图书信息.
它定义了数据注释属性(如[Required])来定义属性的验证. DTO由ABP框架自动验证.

IBookAppService

using System;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;

namespace Zto.BookStore.Books
{
    public interface IBookAppService:
           ICrudAppService<     //Defines CRUD methods
            BookDto,            //Used to show books
            Guid,               //Primary key of the book entity
            PagedAndSortedResultRequestDto, //Used for paging/sorting
            CreateUpdateBookDto>            //Used to create/update a book
    {

    }
}

继承ICrudAppService<>

1.7 *.BookStore.Application

基本设置

修改默认命名空间为Zto.BookStore
创建文件夹Books

项目引用

*.Application.Contracts

依赖包

Volo.Abp.Ddd.Application

创建`AbpModule`

在文件夹Books下创建AbpModule:

using Volo.Abp.Localization;
using Volo.Abp.Modularity;

namespace Zto.BookStore
{
    [DependsOn(
        typeof(BookStoreDomainModule),
        typeof(BookStoreApplicationContractsModule),
         typeof(AbpLocalizationModule)
        )]
    public class BookStoreApplicationModule : AbpModule
    {
    }
}

特别指出的是，依赖模块AbpLocalizationModule,支持本地化

对象映射

知识点 AutoMap

文档

AutoMapper——Map之实体的桥梁

AutoMapper官网

官方文档

基本使用

Setup

var config = new MapperConfiguration(cfg => {
    cfg.AddProfile<AppProfile>();
    cfg.CreateMap<Source, Dest>();
});

var mapper = config.CreateMapper();
// or
IMapper mapper = new Mapper(config);
var dest = mapper.Map<Source, Dest>(new Source());

Starting with 9.0, the static API is no longer available.

Gathering configuration before initialization

AutoMapper also lets you gather configuration before initialization:

var cfg = new MapperConfigurationExpression();
cfg.CreateMap<Source, Dest>();
cfg.AddProfile<MyProfile>();
MyBootstrapper.InitAutoMapper(cfg);

var mapperConfig = new MapperConfiguration(cfg);
IMapper mapper = new Mapper(mapperConfig);

Profile Instances

A good way to organize your mapping configurations is with profiles. Create classes that inherit from Profile and put the configuration in the constructor:

（通过自定义``Profile 的子类，设置映射配置）

// This is the approach starting with version 5
public class OrganizationProfile : Profile
{
	public OrganizationProfile()
	{
		CreateMap<Foo, FooDto>();
		// Use CreateMap... Etc.. here (Profile methods are the same as configuration methods)
	}
}

Assembly Scanning for auto configuration

Profiles can be added to the main mapper configuration in a number of ways, either directly:

（通过AddProfile将自定义``Profile 的子类添加到映射配置中）

cfg.AddProfile<OrganizationProfile>();
cfg.AddProfile(new OrganizationProfile());

or by automatically scanning for profiles:

（通过程序集扫描profiles类到映射配置中）

// Scan for all profiles in an assembly
// ... using instance approach:

var config = new MapperConfiguration(cfg => {
    cfg.AddMaps(myAssembly);
});
var configuration = new MapperConfiguration(cfg => cfg.AddMaps(myAssembly));

// Can also use assembly names:
var configuration = new MapperConfiguration(cfg =>
    cfg.AddMaps(new [] {
        "Foo.UI",
        "Foo.Core"
    });
);

// Or marker types for assemblies:
var configuration = new MapperConfiguration(cfg =>
    cfg.AddMaps(new [] {
        typeof(HomeController),
        typeof(Entity)
    });
);

AutoMapper will scan the designated assemblies for classes inheriting from Profile and add them to the configuration.

配置对象映射关系

在将Book返回到表示层时,需要将Book实体转换为BookDto对象. AutoMapper库可以在定义了正确的映射时自动执行此转换.

因此你只需在*.BookStore.Application项目的中:

中定义映射:

第一步：自定义BookStoreApplicationAutoMapperProfile继承自 Profile，对象映射配置都在这里设置

BookStoreApplicationAutoMapperProfile.cs

    public class BookStoreApplicationAutoMapperProfile : Profile
    {
        public BookStoreApplicationAutoMapperProfile()
        {
            CreateMap<Book, BookDto>();
            CreateMap<CreateUpdateBookDto, Book>();
        }
    }

第二步：配置AbpAutoMapperOptions

使BookStoreApplicationModule模块依赖AbpAutoMapperModule模块，并在的ConfigureServices方法中配置AbpAutoMapperOptions，本示例是通过扫描程序集的方式搜索Porfile类，并添加到AutoMapper配置中

using Volo.Abp.AutoMapper;
using Volo.Abp.Localization;
using Volo.Abp.Modularity;

namespace Zto.BookStore
{
    [DependsOn(
        ...
        typeof(AbpAutoMapperModule)
        )]
    public class BookStoreApplicationModule : AbpModule
    {
        public override void ConfigureServices(ServiceConfigurationContext context)
        {
            Configure<AbpAutoMapperOptions>(options =>
            {
                //通过扫描程序集的方式搜索`Porfile`类，并添加到AutoMapper配置中
                options.AddMaps<BookStoreApplicationModule>(); 
            });
        }
    }
}

源码代码分析

以下代码：

options.AddMaps<BookStoreApplicationModule>();

调用源码：

   public class AbpAutoMapperOptions
   {
        public AbpAutoMapperOptions()
        {
            Configurators = new List<Action<IAbpAutoMapperConfigurationContext>>();
            ValidatingProfiles = new TypeList<Profile>();
        }
       
       public void AddMaps<TModule>(bool validate = false)
        {
            var assembly = typeof(TModule).Assembly;

            Configurators.Add(context =>
            {
                context.MapperConfiguration.AddMaps(assembly);
            });
           
            ......
   }

这里使用

context.MapperConfiguration.AddMaps(assembly);

扫描程序集的方式搜索Profile类添加到AutoMapper配置中

对象转换

配置对象映射关系后，可以使用如下代码进行对象转换：

 var bookDto = ObjectMapper.Map<Book, BookDto>(book);
 var bookDtos = ObjectMapper.Map<List<Book>, List<BookDto>>(books)

其中，

ObjectMappers 是ApplicationService类内置的对象，只要xxxAppService继承自ApplicationService即可使用

源码分析

IObjectMapper:

namespace Volo.Abp.ObjectMapping
{
    //
    // 摘要:
    //     Defines a simple interface to automatically map objects.
    public interface IObjectMapper
    {
        //
        // 摘要:
        //     Gets the underlying Volo.Abp.ObjectMapping.IAutoObjectMappingProvider object
        //     that is used for auto object mapping.
        IAutoObjectMappingProvider AutoObjectMappingProvider
        {
            get;
        }
        TDestination Map<TSource, TDestination>(TSource source); //A
        TDestination Map<TSource, TDestination>(TSource source, TDestination destination);//A
    }
}

在模块AbpObjectMappingModule

public class AbpObjectMappingModule : AbpModule
 {
        ......
            
        public override void ConfigureServices(ServiceConfigurationContext context)
        {
            context.Services.AddTransient(
                typeof(IObjectMapper<>),
                typeof(DefaultObjectMapper<>)
            );
        }
  }

设置了IObjectMapper的默认实现类DefaultObjectMapper

   public class DefaultObjectMapper : IObjectMapper, ITransientDependency
   {
        public IAutoObjectMappingProvider AutoObjectMappingProvider { get; }
       
        public virtual TDestination Map<TSource, TDestination>(TSource source)
        {
            .....

            return AutoMap(source, destination);
        }
       public virtual TDestination Map<TSource, TDestination>(TSource source, TDestination destination)
        {
            ....
            return AutoMap(source, destination);
        }
       
        protected virtual TDestination AutoMap<TSource, TDestination>(object source)
        {
            return AutoObjectMappingProvider.Map<TSource, TDestination>(source);
        }

        protected virtual TDestination AutoMap<TSource, TDestination>(TSource source, TDestination destination)
        {
            return AutoObjectMappingProvider.Map<TSource, TDestination>(source, destination);
        }
   }

根据以上代码可以看出：ObjectMapper.Map<S,D>()最终调用的都是

AutoObjectMappingProvider.Map<TSource, TDestination>(source);
or
AutoObjectMappingProvider.Map<TSource, TDestination>(source, destination);

-->IAutoObjectMappingProvider AutoObjectMappingProvider-->AutoMapperAutoObjectMappingProvider

  public class AutoMapperAutoObjectMappingProvider : IAutoObjectMappingProvider
  {
        public IMapperAccessor MapperAccessor { get; }
      
        public virtual TDestination Map<TSource, TDestination>(object source)
        {
            return MapperAccessor.Mapper.Map<TDestination>(source); //B
        }

        public virtual TDestination Map<TSource, TDestination>(TSource source, TDestination destination)
        {
            return MapperAccessor.Mapper.Map(source, destination);  //B
        }
  }

-->IMapperAccessor MapperAccessor

    public interface IMapperAccessor
    {
        IMapper Mapper { get; }
    }

-->即调用的是MapperAccessor.Mapper的Map()方法,

那MapperAccessor.Mapper到底是谁呢?

-->AbpAutoMapperModule模块

    [DependsOn(
        typeof(AbpObjectMappingModule),
        typeof(AbpObjectExtendingModule),
        ....
        )]
    public class AbpAutoMapperModule : AbpModule
    {
        public override void ConfigureServices(ServiceConfigurationContext context)
        {
            context.Services.AddAutoMapperObjectMapper();

            var mapperAccessor = new MapperAccessor();
            context.Services.AddSingleton<IMapperAccessor>(_ => mapperAccessor);
            context.Services.AddSingleton<MapperAccessor>(_ => mapperAccessor);
        }

        public override void OnPreApplicationInitialization(ApplicationInitializationContext context)
        {
            CreateMappings(context.ServiceProvider);
        }
        
         private void CreateMappings(IServiceProvider serviceProvider)
        {
            using (var scope = serviceProvider.CreateScope())
            {
                var options = scope.ServiceProvider.GetRequiredService<IOptions<AbpAutoMapperOptions>>().Value;
                ......
                var mapperConfiguration = new MapperConfiguration(mapperConfigurationExpression =>
                {
                    ConfigureAll(new AbpAutoMapperConfigurationContext(mapperConfigurationExpression, scope.ServiceProvider));
                });
               ......
                 var mapperConfiguration = new MapperConfiguration(
                {
                    ....
                });
                scope.ServiceProvider.GetRequiredService<MapperAccessor>().Mapper = mapperConfiguration.CreateMapper(); //C
            }
        }

--> var mapperAccessor = new MapperAccessor();注册了单例

-->scope.ServiceProvider.GetRequiredService<MapperAccessor>().Mapper = mapperConfiguration.CreateMapper();

这样步骤C的代码使得步骤B中的MapperAccessor.Mapper（其类型为：Volo.Abp.AutoMapper.IMapperAccessor）得到了实例化

综上所有步骤，等价于

AutoMapperAutoObjectMappingProvider.MapperAccessor.Mapper = mapperConfiguration.CreateMapper();

这就是我们熟悉的：

var config = new MapperConfiguration(cfg => {
    cfg.AddProfile<AppProfile>();
    cfg.CreateMap<Source, Dest>();
});

IMapper mapper = config.CreateMapper();
var dest = mapper.Map<Source, Dest>(new Source());

BookStoreAppService

在文件夹Books下创建BookStoreAppService.cs

这是一个抽象类，其它xxxApplicationService都将继续自它：

    /// <summary>
    /// Inherit your application services from this class.
    /// </summary>
    public abstract class BookStoreAppService : ApplicationService
    {
        protected BookStoreAppService()
        {
            LocalizationResource = typeof(BookStoreResource);
        }
    }

设置本地化资源

LocalizationResource = typeof(BookStoreResource);

BookAppService.cs

BookAppService继承上一节定义的抽象类BookStoreAppService，

using System;
using Volo.Abp.Application.Dtos;
using Volo.Abp.Application.Services;
using Volo.Abp.Domain.Repositories;

namespace Zto.BookStore.Books
{
    public class BookAppService :
            CrudAppService<
                Book,                //The Book entity
                BookDto,             //Used to show books
                Guid,                //Primary key of the book entity
                PagedAndSortedResultRequestDto, //Used for paging/sorting
                CreateUpdateBookDto>,           //Used to create/update a book
            IBookAppService                     //implement the IBookAppService
    {

        public BookAppService(IRepository<Book, Guid> repository)
            : base(repository)
        {
        }

    }
}

2.`Authors`领域

这一部分在第一部分的搭建好基础框架的基础上，创建Authors 的相关知识，

文本档可参见

[Authors: Domain layer][https://docs.abp.io/en/abp/latest/Tutorials/Part-6?UI=MVC&DB=EF]

abp-vnext-ZeroToOne系列

前言

1.初步构建项目架构

1.1 *.Domain.Shared

基本设置

依赖包

知识点: Abp模块化

创建AbpModule

创建BookType

Book相关常量

本地化

创建本地化资源

1.2 *.Domain

基本设置

项目引用

依赖包

创建AbpModule

创建Book领域模型

项目常量值类BookStoreConsts

1.3 *.EntityFrameworkCore

项目引用

依赖包

创建AbpModule

创建DbContext

BookStore的EFcore 实体模型映射

命令行中执行数据库迁移

1.4 *.EntityFrameworkCore.DbMigrations

基本设置

项目引用

依赖包

创建AbpModule

迁移DbContexnt

设计时创建DbContext

什么是设计时创建DbContext

实现IDesignTimeDbContextFactory<>

在项目*.EntityFrameworkCore.DbMigrations中数据库迁移的局限性

迁移接口：IBookStoreDbSchemaMigrator

数据库迁移服务

简化BookStoreDbMigrationService

1.5 *.DbMigrator

基本设置

项目引用

依赖包

创建AbpModule

创建HostServer

知识点：IHostedService

数据库迁移HostedService

依赖注入HostedService

知识点：Serilog

执行数据库迁移

种子数据

IDataSeedContributor:种子数贡献者

IDataSeeder服务:执行种子数据

dataSeeder.SeedAsync(tenant?.Id)干了啥？

1.6 *.Application.Contracts

应用服务层

基本设置

项目引用

依赖包

创建AbpModule

DTO

BooksDto

CreateUpdateBookDto

IBookAppService

1.7 *.BookStore.Application

基本设置

项目引用

依赖包

创建AbpModule

对象映射

知识点 AutoMap

基本使用

配置对象映射关系

源码代码分析

对象转换

源码分析

BookStoreAppService

设置本地化资源

BookAppService.cs

2.Authors领域

创建`AbpModule`

创建`BookType`

创建`AbpModule`

创建`Book`领域模型

项目常量值类`BookStoreConsts`

创建`AbpModule`

创建`DbContext`

创建`AbpModule`

迁移`DbContexnt`

设计时创建`DbContext`

什么是设计时创建`DbContext`

实现`IDesignTimeDbContextFactory<>`

在项目`*.EntityFrameworkCore.DbMigrations`中数据库迁移的局限性

简化`BookStoreDbMigrationService`

创建`AbpModule`

创建`HostServer`

数据库迁移`HostedService`

依赖注入`HostedService`

`IDataSeedContributor`:种子数贡献者

`IDataSeeder`服务:执行种子数据

创建`AbpModule`

`BooksDto`

`CreateUpdateBookDto`

创建`AbpModule`

2.`Authors`领域