查询基础机构检索使用LINQ所有派生​​实体的数据实体

Question

我已经按照我的模型类：

public class Party 
{ 
    public int Id {get; set;} 
} 

[Table("Person")] 
public class Person:Party 
{ 
    public string FirstName {get; set;} 
    public string LastName {get; set;} 
} 

[Table("Organization")] 
public class Organization:Party 
{ 
    public string Name {get; set;} 
} 

我如何可以查询在Parties并返回结果如下PartyViewModel，使用LINQ到实体Fluent API？

public PartyViewModel 
{ 
    public int Id {get;set;} 
    public string FirstName {get;set;} 
    public string LastName {get;set;} 
    public string Name {get;set;} 
} 

e.g如果我有以下记录：

 Person Table 
------------------------ 
Id FirstName LastName 
0  John  Smith 


    Organization Table 
------------------------ 
Id   Name 
1  Microsoft 

我想，该查询返回：

  PartyViewModel 
--------------------------------- 
Id FirstName LastName Name 
0  John  Smith  null 
1  null  null  Microsoft 

Answer 1

使用SQL UNION应该得到你所需要的。

var q1 = from p in db.Persons 
     select new PartyViewModel { 
      Id = p.Id, 
      FirstName = p.FirstName, 
      LastName = p.LastName, 
      Name = null 
     }; 
var q2 = from o in db.Organizations 
     select new PartyViewModel { 
      Id = o.Id, 
      FirstName = null, 
      LastName = null, 
      Name = o.Name 
     }; 

var vm = q1.Union(q2).ToList();