实体框架一对一导航属性不加载 [英] Entity Framework One to One navigation property not loading

问题描述

所以我有一个简单的数据库包含两个表的设置与代码首先使用实体​​框架6.02。在提交表具有与tbl_lst_Company表以一对一的关系。他们是由该公司和CompanyID领域相关的。

So I have a simple database with two tables setup with code first using entity framework 6.02. The Submission table has a one to one relationship with the tbl_lst_Company table. They are related by the company and CompanyID fields.

public partial class Submission
{
    public Submission()
    {           
        this.Company = new tbl_lst_Company();
    }
    public int Keytbl { get; set; }
    public int companyid { get; set; }
    public virtual tbl_lst_Company Company { get; set; }        
}

public partial class tbl_lst_Company
{       
    public int CompanyID { get; set; }
    public string Company { get; set; }
    public virtual Submission Submission { get; set; }
}

和这里是流利的映射：

    public SubmissionMap()
    {
        // Primary Key
        this.HasKey(t => t.Keytbl);
        // Table & Column Mappings
        this.ToTable("Submissions");
        this.Property(t => t.Keytbl).HasColumnName("Keytbl");
        this.Property(t => t.companyid).HasColumnName("company");

        this.HasRequired(q => q.Company).
        WithOptional().Map(t => t.MapKey("Company"));
    }

    public tbl_lst_CompanyMap()
    {
        // Primary Key
        this.HasKey(t => t.CompanyID);

        // Properties
        this.Property(t => t.Company)
            .IsRequired()
            .HasMaxLength(150);
        // Table & Column Mappings
        this.ToTable("tbl_lst_Company");
        this.Property(t => t.CompanyID).HasColumnName("CompanyID");
        this.Property(t => t.Company).HasColumnName("Company");
    }

下面是我正在测试上面的实现我的单元测试：

Here is my unit test I am running to test the above implementation:

    public void download_data() {
        var db = new SubmissionContext();
        db.Configuration.LazyLoadingEnabled = true;
        var subs = (from s in db.Submissions                     
                    select s).Take(100);
        var x = subs.First().Company;
        var a = subs.ToArray();            
    }

我的问题是，公司字段总是空当我运行这个测试。如果我explicilty从s在db.Submissions.Include（「本公司」）说，后来公司字段不为空，但我不得不急于负载的导航属性。我希望公司的导航属性延迟加载。至于我可以告诉大家，我做的一切它是假设做的方式，但它不工作。我在做什么错了？

My problem is that the Company field is always null when I run this test. If I explicilty say from s in db.Submissions.Include("Company"), then the Company field is not null but I have to eager load the navigation property. I want the Company navigation property to lazy load. As far as I can tell I am doing everything the way it is suppose to be done but it is not working. What am I doing wrong?

感谢

推荐答案

所以我想通出来，有一些东西错了，但这里是为我工作的解决方案。你并不需要实例化一个单一的导航属性。这将导致它总是空。您仍然需要实例化的导航属性，如果它是一个对象的ICollection。还有一些其他的小事情为好。感谢您的帮助。

So I figured it out, there were a number of things wrong, but here is the solution that worked for me. You do not need to instantiate a single navigation property. This will cause it to be always null. You still need to instantiate the navigation property if it is an ICollection of objects. There were a few other minor things as well. Thanks for the help.

public partial class Submission
{       
    public int Keytbl { get; set; }
    public int Company { get; set; }
    public virtual tbl_lst_Company tbl_lst_Company{ get; set; }        
}

public partial class tbl_lst_Company
{       
public tbl_lst_Company() {
        this.Submissions = new List<Submission>();
}
    public int CompanyID { get; set; }
    public string Company { get; set; }
    public virtual ICollection<Submission> Submissions { get; set; }
}

public tbl_lst_CompanyMap()
{
    // Primary Key
    this.HasKey(t => t.CompanyID);

    // Properties
    this.Property(t => t.Company)
        .IsRequired()
        .HasMaxLength(150);
    // Table & Column Mappings
    this.ToTable("tbl_lst_Company");
    this.Property(t => t.CompanyID).HasColumnName("CompanyID");
    this.Property(t => t.Company).HasColumnName("Company");
}

public SubmissionMap()
{
    // Primary Key
    this.HasKey(t => t.Keytbl);
    // Table & Column Mappings
    this.ToTable("Submissions");
    this.Property(t => t.Keytbl).HasColumnName("Keytbl");
    this.Property(t => t.Company).HasColumnName("Company");

    this.HasOptional(t => t.tbl_lst_Company)
    .WithMany(t => t.Submissions)
.HasForeignKey(d => d.Company);
}

[TestMethod]
public void test_lazy_loading() {
    using (var db = new SubmissionContext()) {
    var subs = (from s in b.Submissions                     
                   select s);
    var x = subs.First().tbl_lst_Company;
    Assert.AreEqual(x, null, "Lazy Loading Failed");
    }
}

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