实体框架加载所有导航属性 [英] EntityFramework Eager Load all Navigation Properties

问题描述

我使用DI和IoC的Repository模式。

我已经在我的存储库中创建了一个函数：

$ b $其中T：class
{
返回_dbContext.Set< T>（）。包含（（id）包括）.Find（ID）;
}

这将真正加载我的实体中的一个导航属性。

但如果我的实体看起来像这样：

  public class Blog：PrimaryKey 
 {
 public作者作者{get; set;} 
 public ICollection< Post>帖子{get; set;} 
} 
  

我将如何加载作者和帖子？我真的要做：

  _dbContext.Set&T;（）。Include（Author）。帖子）找到（ID）。 
  

不可避免地产生这样的功能：

  T EagerGetById< T>（Guid id，string include，string include2，string include3）其中T：class 
 {
 return _dbContext.Set&T; .INCLUDE（包括）.INCLUDE（include2）.INCLUDE（include3）.Find（ID）; 
} 
  

因为对于 Generic Repository！

解决方案

如果你不想使用字符串，你也可以这样做通过使用返回导航属性的表达式来加载任何N个包含。 （原始来源此处）

  public IQueryable< TEntity> GetAllIncluding（params Expression< Func< TEntity，object>> [] includeProperties）
 {
 IQueryable< TEntity> queryable = GetAll（）; 
 foreach（表达式 {
 queryable = queryable.Include< TEntity，object>（includeProperty）; 
} 
 
返回可查询; 
} 
  

I'm using the Repository pattern with DI and IoC.

I have created a function in my Repository:

T EagerGetById<T>(Guid id, string include) where T : class
{
    return _dbContext.Set<T>().Include(include).Find(id);
}

This will eagerly load one navigation property in my entity right.

But if my entity looks like this:

public class Blog : PrimaryKey
{
    public Author Author {get;set;}
    public ICollection<Post> Posts {get;set;}
}

How would I get eager loading for Author and Posts? Would I literally have to do:

_dbContext.Set<T>().Include("Author").Include("Posts").Find(id);

inevitably producing a function like this:

T EagerGetById<T>(Guid id, string include, string include2, string include3) where T : class
{
    return _dbContext.Set<T>().Include(include).Include(include2).Include(include3).Find(id);
}

Because that would be really inefficient for a Generic Repository!

解决方案

If you don't want to use strings, you can also do the same for any N number of includes by using an expression which returns the navigation properties to be eager loaded. (original source here)

public IQueryable<TEntity> GetAllIncluding(params Expression<Func<TEntity, object>>[] includeProperties) 
{
   IQueryable<TEntity> queryable = GetAll();
   foreach (Expression<Func<TEntity, object>> includeProperty in includeProperties) 
   {
      queryable = queryable.Include<TEntity, object>(includeProperty);
   }

   return queryable;
}

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