使用EntityFramework包含多个表

Question

我有3张表格，如下图所示

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我在c#上有实体框架codefirst模型(自动生成)

我正在尝试从每个元素的包含附件的实体列表中获取IEnumerable，我希望每个附件的AttachmentType都包含这些附件元素。

为了更好地演示，我需要：

IEnumerable<Registry> registries = GetTableData();
string oneofthedesiredname = registries
.First()
.Attachments
.First()
.AttachmentType.Name; //I want that, this definition works but its null

使用GetTableData()方法类似于

public IEnumerable<Registry> GetTableData()
    {
        IQueryable<Registry> _registries = _entities.Registry;
        IEnumerable<Registry> data;
        data = _registries
        .Where(p=>p.IsDeleted==false)
        .Include(p=>p.Attachments.Where(x=>x.IsDeleted==false))
        .AsEnumerable();//this query should have change because I cant get Attachmenttypes from this            
        return data;
    }

谢谢大家，感谢你们的帮助。

Answer 1

还必须在查询中为AttachmentType添加额外的Include。

public IEnumerable<Registry> GetTableData()
{
    IQueryable<Registry> _registries = _entities.Registry;

    IEnumerable<Registry> data = _registries
        .Include(x => x.Attachments)
        .Include("Attachments.AttachmentType")
         // here do necessary filtering with Where()
         // ...

    return data;
}

Answer 2

使用此函数

public IEnumerable<Registry> GetTableData()
    {
        IQueryable<Registry> _registries = _entities.Registry,where(m=>m.IsDeleted==false);
        IEnumerable<Registry> data;
        data = _registries     .Include(p=>p.Attachments.Where(x=>x.IsDeleted==false)).
 include(p=>p.AttachmentType).AsEnumerable();
        return data;
    }