實體框架CodeFirst許多與其他信息

Question

一對多的關係，我有以下型號：

class Contract 
{ 
    string ContractID{get;set;} 
    ICollection<Part> Parts{get;set;} 
} 

class Part 
{ 
    string PartID{get;set;} 
    ICollection<Contract> Contracts{get;set;} 
} 

的問題是，部分與合同之間的關係，還包含以下信息：

class ContractParts 
{ 
    Contract{get;set;} 
    Part{get;set;} 
    Date{get;set;} //additional info 
    Price{get;set;} //additional info 
} 

我將如何爲此編寫實體上下文？

Answer 1

在這種情況下，你必須這樣建模您的實體：

public class Contract 
{ 
    public virtual string ContractId { get; set; } 
    public virtual ICollection<ContractPart> ContractParts { get; set; } 
} 

public class Part 
{ 
    public virtual string PartId { get;set; } 
    public virtual ICollection<ContractPart> ContractParts { get; set; } 
} 

public class ContractPart 
{ 
    public virtual string ContractId { get; set; } 
    public virtual string PartId { get; set; } 
    public virtual Contract Contract { get; set; } 
    public virtual Part Part { get; set; } 
    public virtual string Date { get; set; } //additional info 
    public virtual decimal Price { get; set; } //additional info 
} 

在導出的上下文必須定義：

protected override void OnModelCreating(DbModelBuilder modelBuilder) 
{ 
    modelBuilder.Entity<ContractPart>() 
       .HasKey(cp => new { cp.ContractId, cp.PartId }); 

    modelBuilder.Entity<Contract>() 
       .HasMany(c => c.ContractParts) 
       .WithRequired() 
       .HasForeignKey(cp => cp.ContractId); 

    modelBuilder.Entity<Part>() 
       .HasMany(p => p.ContractParts) 
       .WithRequired() 
       .HasForeignKey(cp => cp.PartId); 
} 

Answer 2

也許有更好的方式做的是這個答案？ Create code first, many to many, with additional fields in association table

它不需要流暢的API，也可以在連接表上設置PK。