Question

我有以下课程：

public class User
{        
    public Guid Id { get; set; }
    public string Name { get; set; }
    public bool Active { get; set; }
    public string UserName { get; set; }       
    //keys       
    public ICollection<Conversation> Conversations { get; set; }
}
public class Conversation
{        
    public Guid ID { get; set; }
    public ICollection<Message> Messages { get; set; }
    public User RecipientUser { get; set; }
    public User SenderUser { get; set; }
    public DateTime CreatedDate { get; set; }
    public DateTime ModifiedDate { get; set; }
}

我使用流畅的Api使用EntityTypeConfiguration：

public class UserConfig : EntityTypeConfiguration<User>
{
    public UserConfig()
    {
        HasMany(x => x.Conversations).WithRequired(x => x.RecipientUser);
    }
}
public class ConversationConfig : EntityTypeConfiguration<Conversation>
{
    public ConversationConfig()
    {
        HasKey(x => x.ID);
        HasRequired(x => x.RecipientUser).WithMany(x => x.Conversations);                   
    }
}

这是一个简单的聊天应用程序。如果我当前用户比我是消息的发送者。收件人用户是我发送邮件的用户。请建议我如何配置我的EntityTypeConfiguration。我收到的错误如下：违反了多重性约束。角色＆＃39; Conversation_RecipientUser_Target＆＃39;关系＆＃39; DataAcessLayer.Conversation_RecipientUser＆＃39;具有多重性1或0..1。

Answer 1

删除此部分

HasRequired(x => x.RecipientUser).WithMany(x => x.Conversations);

来自ConversationConfig的

Answer 2

我更新了我的Conversation课程，如下所示：

public class Conversation
{
    public int ID { get; set; }
    public int SenderUserID { get; set; }
    public User SenderUser { get; set;}
    public int RecipientUserID { get; set; }
    public User RecipientUser { get; set; }
}

并删除了我的UserConfig流畅的api。相反，我在ConversationConfig.cs文件中添加了映射：

public class ConversationConfig : EntityTypeConfiguration<Conversation>
{
   public ConversationConfig()
    {
        HasKey(c => c.ID);
        HasRequired(c => c.SenderUser).WithMany(u => u.Conversations)
                          .HasForeignKey(c => c.SenderUserID).WillCascadeOnDelete(true);
        HasRequired(c => c.RecipientUser).WithMany()
                          .HasForeignKey(c => c.RecipientUserID).WillCascadeOnDelete(false);          
    }
}

（其中一个外键没有级联删除，因为这会导致SQL-Server错误：多个级联路径）。这很有效。谢谢你的帮助!!!

EF Codefirst - 使用流畅的api进行表映射

2 个答案: