无法将位置转换为 ILocation

Question

我遇到了一个相当奇怪的转换错误。这是代码：

public class OrganizationLocation : IOrganizationLocation
{
    public Guid Id { get; set; }
    public string Name { get; set; }
}

public interface IOrganizationLocation
{
    string Name { get; }
}

public class Organization : IOrganization
{
    public Guid Id { get; set; }
    public string Alias { get; set; }

    public virtual ICollection<OrganizationLocation> Location { get; set; }

    public ICollection<IOrganizationLocation> Locations
    {
        get
        {
            return (ICollection<IOrganizationLocation>) Location;
        }
    }
}

public interface IOrganization
{
    string Alias { get; }
    ICollection<IOrganizationLocation> Locations { get; }
}

现在，当我尝试通过服务（后端数据层是 EF6）运行时，"Location" 变量具有所有值，但是，"Locations" 变量无法投掷。如果我尝试进行安全转换，每次都会返回 null。

我不明白为什么转换会失败？它具有相同的字段，都是 ICollection 类型，那么为什么我得到一个 HashSet？

我这样做的原因是因为 EF6 框架能够将此 class 视为 table 它需要具有具体类型和 public get/set。但是，我不想公开它，所以我改用接口，然后在调用接口时注入 class 。这样我只公开了get方法，在它之上我只公开了接口层。

Unable to cast object of type 'System.Collections.Generic.HashSet`1[Namespace.OrganizationLocation]' to type 'System.Collections.Generic.ICollection`1[Namespace2.IOrganizationLocation]'.

Answer 1

我可以通过将代码更改为以下内容来解决此问题：

public class OrganizationLocation : IOrganizationLocation
{
    public Guid Id { get; set; }
    public string Name { get; set; }
}

public interface IOrganizationLocation
{
    string Name { get; }
}

public class Organization : IOrganization
{
    public Guid Id { get; set; }
    public string Alias { get; set; }

    public virtual ICollection<OrganizationLocation> Location { get; set; }

    public IEnumerable<IOrganizationLocation> Locations => Location
}

public interface IOrganization
{
    string Alias { get; }
    IEnumerable<IOrganizationLocation> Locations { get; }
}

无法将位置转换为 ILocation

Unable to cast location to ILocation

c#

ef-database-first

entity-framework-6

asp.net-mvc-5