c# - Entity Framework 只读集合

考虑一个域，其中客户，公司，员工等具有ContactInfo属性，而该属性又包含一组地址，电话，电子邮件等，等等。

这是我的缩写ContactInfo:

public class ContactInfo : Entity<int>
{
    public ContactInfo()
    {
        Addresses = new HashSet<Address>();
    }

    public virtual ISet<Address> Addresses { get ; private set; }

    public Address PrimaryAddress
    {
        get { return Addresses.FirstOrDefault(a => a.IsPrimary); }
    }

    public bool AddAddress(Address address)
    {
        // insure there is only one primary address in collection
        if (address.IsPrimary)
        {
            if (PrimaryAddress != null)
            {
                PrimaryAddress.IsPrimary = false;
            }
        }
        else
        {
            // make sure the only address in collection is primary
            if (!Addresses.Any())
            {
                address.IsPrimary = true;
            }
        }
        return Addresses.Add(address);
    }
}

一些注意事项(我不确定这些是EF“最佳做法”还是100％):

地址的

集合是虚拟的，允许延迟加载

收集中的私有(private)二传手禁止收集替换

集合是一个ISet，可确保每个联系人没有重复的地址

使用AddAddress方法，我可以确保始终有一个至多1个主要地址。...

我想(如果可能)阻止通过ContactInfo.Addresses.Add()方法添加地址，并强制使用ContactInfo.AddAddress(Address address) ...

我正在考虑通过ReadOnlyCollection公开地址集，但是这可用于Entity Framework(v5)吗？

我将如何处理？

最佳答案

一种方法是使ICollection属性受到保护，并创建一个仅返回ICollection属性列表的IEnumerable新属性。

这样做的缺点是您无法像通过获取居住在该城市的所有contactinfo一样通过ContactInfo查询地址。

这是不可能的:

from c in ContactInfos
where c.Addresses.Contains(x => x.City == "New York")
select c

代码:

public class ContactInfo : Entity<int>
{
    public ContactInfo()
    {
        Addresses = new HashSet<Address>();
    }

    protected virtual ISet<Address> AddressesCollection { get ; private set; }

    public IEnumerable<Address> Addresses { get { return AddressesCollection; }}

    public Address PrimaryAddress
    {
        get { return Addresses.FirstOrDefault(a => a.IsPrimary); }
    }

    public bool AddAddress(Address address)
    {
        // insure there is only one primary address in collection
        if (address.IsPrimary)
        {
            if (PrimaryAddress != null)
            {
                PrimaryAddress.IsPrimary = false;
            }
        }
        else
        {
            // make sure the only address in collection is primary
            if (!Addresses.Any())
            {
                address.IsPrimary = true;
            }
        }
        return Addresses.Add(address);
    }
}