实体框架。明确包含一对二实体

Question

我有一对二的关系：

public class Branch
{
    public Branch()
    {
        Id = Guid.NewGuid();
        AddressInfo = new AddressInfo(this);
    }

    public Guid Id { get; set; }
    public virtual AddressInfo AddressInfo { get; set; }
}

public class AddressInfo
{
    private AddressInfo() {}
    public AddressInfo(Branch b)
    {
        Branch = b;
        BId = bank.Id;
    }
    public virtual Branch Branch { get; set; }
    public string XXX { get; set; }
}

在映射中：

HasRequired(x => x.AddressInfo)
                .WithRequiredPrincipal(x => x.Branch);

简单

from b in dc.Branches
select new { b.Id, b.AddressInfo.XXX };

有效，但我想在这样的查询中加载AddressInfo

var dtos = (from b in dc.Branches
    select new { b /*, b.AddressInfo*/ }).ToList();

如果取消注释, b.AddressInfo，则会出现Multiplicity constraint violated. The role '…' of the relationship '…' has multiplicity 1 or 0..1错误。