|  |  |  | @ -30,7 +30,7 @@ namespace MyCompany.MyProject | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ### 数据库管理系统选择 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | EF Core支持多种数据库管理系统([查看全部](https://docs.microsoft.com/en-us/ef/core/providers/)). ABP框架和本文档不依赖于任何特定的DBMS. | 
			
		
	
		
			
				
					|  |  |  |  | EF Core支持多种数据库管理系统([查看全部](https://docs.microsoft.com/zh-cn/ef/core/providers/)). ABP框架和本文档不依赖于任何特定的DBMS. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 如果要创建一个可重用的[应用程序模块](Modules/Index.md),应避免依赖于特定的DBMS包.但在最终的应用程序中,始终会选择一个DBMS. | 
			
		
	
		
			
				
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					|  |  |  | @ -60,7 +60,7 @@ namespace MyCompany.MyProject | 
			
		
	
		
			
				
					|  |  |  |  | 
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					|  |  |  |  | ### 关于EF Core Fluent Mapping | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | [应用程序启动模板](Startup-Templates/Application.md)已配置使用[EF Core fluent configuration API](https://docs.microsoft.com/en-us/ef/core/modeling/)映射你的实体到数据库表. | 
			
		
	
		
			
				
					|  |  |  |  | [应用程序启动模板](Startup-Templates/Application.md)已配置使用[EF Core fluent configuration API](https://docs.microsoft.com/zh-cn/ef/core/modeling/)映射你的实体到数据库表. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 你依然为你的实体属性使用**data annotation attributes**(像`[Required]`),而ABP文档通常遵循**fluent mapping API** approach方法. 如何使用取决与你. | 
			
		
	
		
			
				
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					|  |  |  | @ -272,6 +272,285 @@ public async override Task DeleteAsync( | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
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					|  |  |  |  | ## 加载关联实体 | 
			
		
	
		
			
				
					|  |  |  |  | 
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					|  |  |  |  | 假设你拥有带有`OrderLine`集合的`Order`,并且`OrderLine`具有`Order`的导航属性: | 
			
		
	
		
			
				
					|  |  |  |  | 
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					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | using System; | 
			
		
	
		
			
				
					|  |  |  |  | using System.Collections.Generic; | 
			
		
	
		
			
				
					|  |  |  |  | using System.Collections.ObjectModel; | 
			
		
	
		
			
				
					|  |  |  |  | using Volo.Abp.Auditing; | 
			
		
	
		
			
				
					|  |  |  |  | using Volo.Abp.Domain.Entities; | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | namespace MyCrm | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     public class Order : AggregateRoot<Guid>, IHasCreationTime | 
			
		
	
		
			
				
					|  |  |  |  |     { | 
			
		
	
		
			
				
					|  |  |  |  |         public Guid CustomerId { get; set; } | 
			
		
	
		
			
				
					|  |  |  |  |         public DateTime CreationTime { get; set; } | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |         public ICollection<OrderLine> Lines { get; set; } //子集合 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |         public Order() | 
			
		
	
		
			
				
					|  |  |  |  |         { | 
			
		
	
		
			
				
					|  |  |  |  |             Lines = new Collection<OrderLine>(); | 
			
		
	
		
			
				
					|  |  |  |  |         } | 
			
		
	
		
			
				
					|  |  |  |  |     } | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |     public class OrderLine : Entity<Guid> | 
			
		
	
		
			
				
					|  |  |  |  |     { | 
			
		
	
		
			
				
					|  |  |  |  |         public Order Order { get; set; } //导航属性 | 
			
		
	
		
			
				
					|  |  |  |  |         public Guid OrderId { get; set; } | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |         public Guid ProductId { get; set; } | 
			
		
	
		
			
				
					|  |  |  |  |         public int Count { get; set; } | 
			
		
	
		
			
				
					|  |  |  |  |         public double UnitPrice { get; set; } | 
			
		
	
		
			
				
					|  |  |  |  |     } | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 然后象下面显示的这样定义数据库映射: | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | builder.Entity<Order>(b => | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     b.ToTable("Orders"); | 
			
		
	
		
			
				
					|  |  |  |  |     b.ConfigureByConvention(); | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |     //定义关系 | 
			
		
	
		
			
				
					|  |  |  |  |     b.HasMany(x => x.Lines) | 
			
		
	
		
			
				
					|  |  |  |  |         .WithOne(x => x.Order) | 
			
		
	
		
			
				
					|  |  |  |  |         .HasForeignKey(x => x.OrderId) | 
			
		
	
		
			
				
					|  |  |  |  |         .IsRequired(); | 
			
		
	
		
			
				
					|  |  |  |  | }); | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | builder.Entity<OrderLine>(b => | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     b.ToTable("OrderLines"); | 
			
		
	
		
			
				
					|  |  |  |  |     b.ConfigureByConvention(); | 
			
		
	
		
			
				
					|  |  |  |  | }); | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 当你查询一个 `Order`, 你可能想要在单个查询中**包含**所有的 `OrderLine`s 或根据需要在**以后加载它们**. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | > 实际上这与ABP框架没有直接关系. 你可以按照 [EF Core 文档](https://docs.microsoft.com/zh-cn/ef/core/querying/related-data/) 了解全部细节. 本节将涵盖与 ABP 框架相关的一些主题. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ### 预先加载 / 包含子对象的加载 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 当你想加载一个带有关联实体的实体时,可以使用不同的选项. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### Repository.WithDetails | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | `IRepository.WithDetailsAsync(...)` 可以通过包含一个关系收集/属性来获得 `IQueryable<T>` . | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例: 获取一个带有 `lines` 的 `order` 对象** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | using System; | 
			
		
	
		
			
				
					|  |  |  |  | using System.Linq; | 
			
		
	
		
			
				
					|  |  |  |  | using System.Threading.Tasks; | 
			
		
	
		
			
				
					|  |  |  |  | using Volo.Abp.Domain.Repositories; | 
			
		
	
		
			
				
					|  |  |  |  | using Volo.Abp.Domain.Services; | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | namespace AbpDemo.Orders | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     public class OrderManager : DomainService | 
			
		
	
		
			
				
					|  |  |  |  |     { | 
			
		
	
		
			
				
					|  |  |  |  |         private readonly IRepository<Order, Guid> _orderRepository; | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |         public OrderManager(IRepository<Order, Guid> orderRepository) | 
			
		
	
		
			
				
					|  |  |  |  |         { | 
			
		
	
		
			
				
					|  |  |  |  |             _orderRepository = orderRepository; | 
			
		
	
		
			
				
					|  |  |  |  |         } | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |         public async Task TestWithDetails(Guid id) | 
			
		
	
		
			
				
					|  |  |  |  |         { | 
			
		
	
		
			
				
					|  |  |  |  |             //通过包含子集合获取一个 IQueryable<T> | 
			
		
	
		
			
				
					|  |  |  |  |             var queryable = await _orderRepository.WithDetailsAsync(x => x.Lines); | 
			
		
	
		
			
				
					|  |  |  |  |              | 
			
		
	
		
			
				
					|  |  |  |  |             //应用其他的 LINQ 扩展方法 | 
			
		
	
		
			
				
					|  |  |  |  |             var query = queryable.Where(x => x.Id == id); | 
			
		
	
		
			
				
					|  |  |  |  |              | 
			
		
	
		
			
				
					|  |  |  |  |             //执行此查询并获取结果 | 
			
		
	
		
			
				
					|  |  |  |  |             var order = await AsyncExecuter.FirstOrDefaultAsync(query); | 
			
		
	
		
			
				
					|  |  |  |  |         } | 
			
		
	
		
			
				
					|  |  |  |  |     } | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | > `AsyncExecuter` 用于执行异步 LINQ 扩展,而无需依赖 EF Core. 如果你将 EF Core NuGet 包引用添加到你的项目中,则可以直接使用 `await query.FirstOrDefaultAsync()`. 但是, 这次你依赖于域层中的 EF 核心.请参阅. 请参阅 [仓储文档](Repositories.md) 以了解更多. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例: 获取一个包含 `lines` 的 `orders` 列表** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithDetails() | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     //通过包含一个子集合获取一个 IQueryable<T> | 
			
		
	
		
			
				
					|  |  |  |  |     var queryable = await _orderRepository.WithDetailsAsync(x => x.Lines); | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |     //执行此查询并获取结果 | 
			
		
	
		
			
				
					|  |  |  |  |     var orders = await AsyncExecuter.ToListAsync(queryable); | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | > 如果你需要包含多个导航属性或集合,`WithDetailsAsync`方法可以获得多个表达参数. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### DefaultWithDetailsFunc | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 如果你没有将任何表达式传递到 `WithDetailsAsync` 方法,则它包括使用你提供的 `DefaultWithDetailsFunc` 选项的所有详细信息. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 你可以在你的 `EntityFrameworkCore` 项目[模块](Module-Development-Basics.md)的  `ConfigureServices`方法为一个实体配置 `DefaultWithDetailsFunc`. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例: 在查询一个 `Order` 时包含 `Lines`** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | Configure<AbpEntityOptions>(options => | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     options.Entity<Order>(orderOptions => | 
			
		
	
		
			
				
					|  |  |  |  |     { | 
			
		
	
		
			
				
					|  |  |  |  |         orderOptions.DefaultWithDetailsFunc = query => query.Include(o => o.Lines); | 
			
		
	
		
			
				
					|  |  |  |  |     }); | 
			
		
	
		
			
				
					|  |  |  |  | }); | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | > 你可以在这里完全使用 EF Core API,因为这位于 EF Core集成项目中. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 然后你可以不带任何参数地调用 `WithDetails` 方法: | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithDetails() | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     //通过包含一个子集合获取一个 IQueryable<T> | 
			
		
	
		
			
				
					|  |  |  |  |     var queryable = await _orderRepository.WithDetailsAsync(); | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |     //执行此查询并获取结果 | 
			
		
	
		
			
				
					|  |  |  |  |     var orders = await AsyncExecuter.ToListAsync(queryable); | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | `WithDetailsAsync()` 执行你已经在 `DefaultWithDetailsFunc` 中设置的表达式. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### 仓储 Get/Find 方法 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 有些标准的 [仓储](Repositories.md) 方法带有可选的 `includeDetails` 参数; | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | * `GetAsync` 和 `FindAsync` 方法带有默认值为 `true` 的 `includeDetails`. | 
			
		
	
		
			
				
					|  |  |  |  | * `GetListAsync` 和 `GetPagedListAsync` 方法带有默认值为 `false` 的 `includeDetails`. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 这意味着,默认情况下返回**包含子对象的单个实体**,而列表返回方法则默认不包括子对象信息.你可以明确通过 `includeDetails` 来更改此行为. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | > 这些方法使用上面解释的 `DefaultWithDetailsFunc` 选项. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例:获取一个包含子对象的 `order`** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithDetails(Guid id) | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     var order = await _orderRepository.GetAsync(id); | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例:获取一个不包含子对象的 `order`** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithoutDetails(Guid id) | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     var order = await _orderRepository.GetAsync(id, includeDetails: false); | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例:获取一个包含子对象的实体列表** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithDetails() | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     var orders = await _orderRepository.GetListAsync(includeDetails: true); | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### 选择 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 存储库模式尝试封装 EF Core, 因此你的选项是有限的. 如果你需要高级方案,你可以按照其中一个选项执行: | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | * 创建自定义存储库方法并使用完整的 EF Core API. | 
			
		
	
		
			
				
					|  |  |  |  | * 在你的项目中引用 `Volo.Abp.EntityFrameworkCore` . 通过这种方式,你可以直接在代码中使用 `Include` 和 `ThenInclude` . | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 请参阅 EF Core 的 [预先加载文档](https://docs.microsoft.com/zh-cn/ef/core/querying/related-data/eager). | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ### 显示 / 延迟加载 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 如果你在查询实体时不包括关系,并且以后需要访问导航属性或集合,则你有不同的选择. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### EnsurePropertyLoadedAsync / EnsureCollectionLoadedAsync | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 仓储提供 `EnsurePropertyLoadedAsync` 和 `EnsureCollectionLoadedAsync` 扩展方法来**显示加载**一个导航属性或子集合. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | **示例: 在需要时加载一个 `Order` 的 `Lines`** | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithDetails(Guid id) | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     var order = await _orderRepository.GetAsync(id, includeDetails: false); | 
			
		
	
		
			
				
					|  |  |  |  |     //order.Lines 此时是空的 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  |     await _orderRepository.EnsureCollectionLoadedAsync(order, x => x.Lines); | 
			
		
	
		
			
				
					|  |  |  |  |     //order.Lines 被填充 | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 如果导航属性或集合已经被加载那么 `EnsurePropertyLoadedAsync` 和 `EnsureCollectionLoadedAsync` 方法不做任何处理. 所以,调用多次也没有问题. | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 请参阅 EF Core 的[显示加载文档](https://docs.microsoft.com/zh-cn/ef/core/querying/related-data/explicit). | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | #### 使用代理的延时加载 | 
			
		
	
		
			
				
					|  |  |  |  | 
 | 
			
		
	
		
			
				
					|  |  |  |  | 在某些情况下,可能无法使用显示加载,尤其是当你没有引用 `Repository` 或 `DbContext`时.延时加载是 EF Core 加载关联属性/集合的一个功能,,当你第一次访问它. | 
			
		
	
		
			
				
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					|  |  |  |  | 启用延时加载: | 
			
		
	
		
			
				
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					|  |  |  |  | 1. 安装 [Microsoft.EntityFrameworkCore.Proxies](https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.Proxies/) 包到你的项目(通常是 EF Core 集成项目) | 
			
		
	
		
			
				
					|  |  |  |  | 2. 为你的 `DbContext` 配置 `UseLazyLoadingProxies` (在 EF Core 项目的模块的 `ConfigureServices` 方法中). 例如: | 
			
		
	
		
			
				
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					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | Configure<AbpDbContextOptions>(options => | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     options.PreConfigure<MyCrmDbContext>(opts => | 
			
		
	
		
			
				
					|  |  |  |  |     { | 
			
		
	
		
			
				
					|  |  |  |  |         opts.DbContextOptions.UseLazyLoadingProxies(); //启用延时加载 | 
			
		
	
		
			
				
					|  |  |  |  |     }); | 
			
		
	
		
			
				
					|  |  |  |  |      | 
			
		
	
		
			
				
					|  |  |  |  |     options.UseSqlServer(); | 
			
		
	
		
			
				
					|  |  |  |  | }); | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
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					|  |  |  |  | 3. 使你的导航属性和集合是 `virtual`. 例如: | 
			
		
	
		
			
				
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					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public virtual ICollection<OrderLine> Lines { get; set; } //虚集合 | 
			
		
	
		
			
				
					|  |  |  |  | public virtual Order Order { get; set; } //虚导航属性 | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
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					|  |  |  |  | 启用延时加载并整理实体后,你可以自由访问导航属性和集合: | 
			
		
	
		
			
				
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					|  |  |  |  | ````csharp | 
			
		
	
		
			
				
					|  |  |  |  | public async Task TestWithDetails(Guid id) | 
			
		
	
		
			
				
					|  |  |  |  | { | 
			
		
	
		
			
				
					|  |  |  |  |     var order = await _orderRepository.GetAsync(id); | 
			
		
	
		
			
				
					|  |  |  |  |     //order.Lines 此时是空的 | 
			
		
	
		
			
				
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					|  |  |  |  |     var lines = order.Lines; | 
			
		
	
		
			
				
					|  |  |  |  |     //order.Lines 被填充 (延时加载) | 
			
		
	
		
			
				
					|  |  |  |  | } | 
			
		
	
		
			
				
					|  |  |  |  | ```` | 
			
		
	
		
			
				
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					|  |  |  |  | 每当你访问属性/集合时,EF Core 都会自动执行额外的查询,从数据库中加载属性/集合. | 
			
		
	
		
			
				
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					|  |  |  |  | > 应谨慎使用延时加载,因为它可能会在某些特定情况下导致性能问题. | 
			
		
	
		
			
				
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					|  |  |  |  | 请参阅 EF Core 的[延时加载文档](https://docs.microsoft.com/zh-cn/ef/core/querying/related-data/lazy). | 
			
		
	
		
			
				
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					|  |  |  |  | ## 访问 EF Core API | 
			
		
	
		
			
				
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					|  |  |  |  | 大多数情况下应该隐藏仓储后面的EF Core API(这也是仓储的设计目地). 但是如果想要通过仓储访问DbContext实现,则可以使用`GetDbContext()`或`GetDbSet()`扩展方法. 例: | 
			
		
	
	
		
			
				
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