实体框架codeFirst许多与其他信息一对多的关系 [英] Entity Framework CodeFirst many to many relationship with additional information

问题描述

我有以下型号：

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

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

问题是，部分与合同之间的关系还包含以下附加信息：

the problem is that the relationship between Part and Contract also contains the following additional information :

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

我怎么会写实体语境呢？

How would I write the Entity Context for this ?

推荐答案

在这种情况下，你必须符合您的实体是这样的：

In such case you must model your entities this way:

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
}

在派生背景下，你必须定义：

In derived context you must define:

protected override void OnModelCreateing(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);  
}

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