如何用Linq和EntityFramework6

我有一个用c#、asp.net-mvc-5和entity-framework-6编写的项目，我有以下类：

public class Profession
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }  
    public string Description { get; set; }
}
public class Person
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public int Id { get; set; }  
    public string Name { get; set; }
}
public class Individuals : Person
{
    public string CPF { get; set; }
    public int Profession_Id { get; set; }
    [ForeignKey("Profession_Id")]
    public Profession Profession { get; set; }
}
public class Corporate : Person
{
    public string CNPJ { get; set; }
}

我的DbContext类是：

public class Context : DbContext
{
    public Context() : base("AppConnectionString") { }
    public DbSet<Profession> Professions { get; set; }
    public DbSet<Person> People { get; set; }
    public DbSet<Individuals> Individuals { get; set; }
    public DbSet<Corporate> Corporations { get; set; }
}

在运行我的应用程序时，将使用以下结构生成数据库：
表People和列Id、Name、CNPJ、CPF和Discriminator。表Professions中有Id和Description列。

这是我的示例项目：

public class Program
{
    public static void Main(string[] args) {
        var context = new Context();
        GenerateDatabase(context);
        // display the data
        System.Console.ReadKey();
    }
    private static void GenerateDatabase(Context context) 
    {
        if (!context.Database.Exists()) 
        {
            context.Database.Create();
            var p1 = new Profession { Description = "Profission 1" };
            var p2 = new Profession { Description = "Profission 2" };
            context.Professions.Add(p1);
            context.Professions.Add(p2);
            context.SaveChanges();
            context.Individuals.Add(new Individuals { Name = "People 1", CPF = "CPF Teste 1", Profession_Id = p1.Id });
            context.Individuals.Add(new Individuals { Name = "People 2", CPF = "CPF Teste 2", Profession_Id = p2.Id });
            context.Corporations.Add(new Corporate { Name = "Person 1", CNPJ = "CNPJ Teste 1" });
            context.Corporations.Add(new Corporate { Name = "Person 2", CNPJ = "CNPJ Teste 2" });
            context.SaveChanges();
        }
    }
}

好吧，在Main方法中，我有以下代码片段来显示数据：

var items = context.People.OfType<Individuals>();
foreach (var item in items)
    System.Console.WriteLine(item.Id.ToString() + " | " + item.Name + " | " item.Profession.Description + " | " + item.GetType().Name);
var items2 = context.People.OfType<Corporation>();
foreach (var item in items2)
    System.Console.WriteLine(items2.Id.ToString() + " - " + items2.Name);

我需要一个串联来对结果进行排序
在本例中，按类的Name属性排序的结果不正确。

+----+----------+--------------+--------------+
| ID | Name     | Profession   | Discriminator|
+----+----------+--------------+--------------+
|  1 | Person 1 | Profission 1 | Individuals  |
|  2 | Person 2 | Profission 1 | Individuals  |
|  3 | Person 1 |              | Corporate    |
|  4 | Person 2 |              | Corporate    |
+----+----------+--------------+--------------+

我需要收集这两种类型的记录以显示在查询页面中。我试着做Concat，就像被告知要做Union all一样。

很快，我测试了一些类似的东西：

var items = context.People.OfType<Individuals>().Include(x => x.Profession).Concat<Individuals>(
    context.People.OfType<Corporate>().Select(x => new Corporate
    {
        Id = x.Id,
        Name = x.Name,
        CNPJ = x.CNPJ
    }));
items = items.OrderBy(x => x.Name);

但是这是错误的，并且没有编译！

如何使用Queryable实现这一点

var items = 
    context.Individuals.Select(x => (Person)x)
    .Concat(context.Corporations.Select(x => (Person)x))
    .OrderBy(x => x.Name);

foreach (var person in items)
{
    Console.WriteLine("{0,-6}{1,-12}{2}", person.Id, person.Name, person.GetType().Name);
}

1     Person 1    Individuals
3     Person 1    Corporate
2     Person 2    Individuals
4     Person 2    Corporate

var items = 
    context.Individuals.Include("Profession").ToArray().Select(x => (Person)x)
    .Concat(context.Corporations.Select(x => (Person)x)
    .OrderBy(x => x.Name);

var items =
    context.Individuals.Select(x => new 
        { 
            Id = x.Id, 
            Name = x.Name, 
            Profession = x.Profession.Description, 
            Type = "Individual" 
        })
    .Concat(context.Corporations.Select(x => new 
        { 
            Id = x.Id, 
            Name = x.Name, 
            Profession = (string)null, 
            Type = "Corporation" 
        }))
    .OrderBy(x => x.Name).ThenBy(x => x.Id);