實體類型需要在EF Core 2.0中定義主鍵

Question

我正在將具有EF Core項目的ASP.NET Core 1.1升級到ASP.NET Core 2.0。

我有以下實體和配置，這是之前的工作：

public class Ebook {  
    public Int32 Id { get; set; } 
    public String Title { get; set; }  
    public virtual ICollection<EbookFile> EbookFiles { get; set; } = new List<EbookFile>();  
    } 

    public class EbookFile {   
    public Int32 EbookId { get; set; } 
    public Int32 FileId { get; set; }  
    public virtual Ebook Ebook { get; set; } 
    public virtual File File { get; set; }  
    } 

    public class File { 
    public Int32 Id { get; set; } 
    public Byte[] Content { get; set; } 
    public virtual ICollection<EbookFile> EbookFiles { get; set; } = new List<EbookFile>(); 
    } 

而且配置爲：

builder.Entity<Ebook>(b => { 
    b.ToTable("Ebooks"); 
    b.HasKey(x => x.Id); 
    b.Property(x => x.Id).ValueGeneratedOnAddOrUpdate().UseSqlServerIdentityColumn(); 
    b.Property(x => x.Title).IsRequired(true).HasMaxLength(200); 
    b.HasIndex(x => x.Title).IsUnique(); 
}); 

builder.Entity<EbookFile>(b => { 
    b.ToTable("EbookFiles"); 
    b.HasKey(x => new { x.EbookId, x.FileId }); 
    b.HasOne(x => x.Ebook).WithMany(x => x.EbookFiles).HasForeignKey(x => x.EbookId).IsRequired(true).OnDelete(DeleteBehavior.Cascade); 
    b.HasOne(x => x.File).WithMany(x => x.EbookFiles).HasForeignKey(x => x.FileId).IsRequired(true).OnDelete(DeleteBehavior.Cascade); 
}); 

builder.Entity<File>(b => { 
    b.ToTable("Files"); 
    b.HasKey(x => x.Id); 
    b.Property(x => x.Id).UseSqlServerIdentityColumn(); 
    b.Property(x => x.Content).IsRequired(false); 
}); 

而且在我的語境I類具有的屬性：

public DbSet<Ebook> Ebooks { get; set; } 
public DbSet<EbookFile> EbookFiles { get; set; } 
public DbSet<File> Files { get; set; } 

當我運行它時，我收到錯誤：

The entity type 'EbookFile' requires a primary key to be defined. 

我在這裏錯過了什麼？ EF Core 2.0有所改變嗎？

Answer 1

除了Ivan的回答，我猜你明白標識列不需要ValueGeneratedOnAddOrUpdate。

可以生成腳手架代碼，在我來說，我使用CatFactory你可以在這個環節檢查：https://www.codeproject.com/Articles/1160615/Generating-Code-for-EF-Core-with-CatFactory

問候