EF 6流利的配置 - 递归嵌套对象与母公司 - TPH

Question

我有它有其自身的集合，并且我想成为空父母财产，如果它是根插件的下列实体：

public class CanvasWidgetQuery 
{ 
    public int CanvasWidgetId { get; set; } 

    public int? ParentCanvasWidgetId { get; set; } 
    public virtual CanvasWidgetQuery ParentCanvasWidget { get; set; } 
    public virtual ICollection<CanvasWidgetQuery> InnerCanvasWidgets { get; set; } 

} 

因为CanvasWidgetQuery实际上只是一个基类（可能是抽象的，但我没有抽象，直到我看到它没有它时才起作用）。我想创建一个通用的映射配置映射派生类型的CanvasWidgetQuery：

public class CanvasWidgetQueryMap<TCanvasWidgetQuery> : EntityTypeConfiguration<TCanvasWidgetQuery> 
    where TCanvasWidgetQuery : CanvasWidgetQuery 
{ 
    public CanvasWidgetQueryMap() 
    { 
     this.HasKey(q => q.CanvasWidgetId); 

     this.HasMany(w => w.InnerCanvasWidgets) 
      .WithOptional(w => w.ParentCanvasWidget) 
      .HasForeignKey(w => w.ParentCanvasWidgetId); 

    } 
} 

无论派生类型，它们都具有这些属性，但不幸的是它抱怨的WithOptional调用（一次2个错误）：

Error 1 Cannot implicitly convert type 'CanvasWidgetQuery' to 'TCanvasWidgetQuery'. An explicit conversion exists (are you missing a cast?) 


Error 2 Cannot convert lambda expression to delegate type 'System.Func<CanvasWidgetQuery,TCanvasWidgetQuery>' because some of the return types in the block are not implicitly convertible to the delegate return type 

如果我提出这样一个水平，以实际派生类型的映射：

public class SearchCanvasWidgetQueryMap : CanvasWidgetQueryMap<SearchCanvasWidgetQuery> 
{ 
    public SearchCanvasWidgetQueryMap() 
    { 
     this.HasMany(w => w.InnerCanvasWidgets) 
      .WithOptional(w => w.ParentCanvasWidget) 
      .HasForeignKey(w => w.ParentCanvasWidgetId); 
    } 
} 

现在抱怨说，它可以不含蓄转换成CanvasWidgetQuery同时SearchCanvasWidgetQuery：

public class SearchCanvasWidgetQuery : CanvasWidgetQuery 
{ 

} 

我怎么能做到什么，我以后

Answer 1

是你是否尝试过定义地图持有其定义层次结构的属性的基类？

e.g：

public class CanvasWidgetQueryMap<CanvasWidgetQuery> : EntityTypeConfiguration<CanvasWidgetQuery> 
{ 
    public CanvasWidgetQueryMap() 
    { 
     this.HasKey(q => q.CanvasWidgetId); 

     this.HasMany(w => w.InnerCanvasWidgets) 
      .WithOptional(w => w.ParentCanvasWidget) 
      .HasForeignKey(w => w.ParentCanvasWidgetId); 

    } 
} 

有一个在这里回答一些很好的附加信息：CTP 4 doesn't consider base class properties如果上面没有达到你以后可能会有所帮助。