c# – Entity Framework 5代码首先无法让模型工作

在这个上再次撕掉我的头发…使用EF 5 Code First,在代码中构建模型 – 编译,所以它在语法上是正确的,但是当代码构建模型时我得到一个例外.这是实体类(我也有vaidation属性,但为了便于阅读,已将它们删除)：

[Table("USERS")]
public class User : IPEntity
{
    #region Constructor (needs to initialize list objects for related entities)

    public User()
    {
        this.Profiles = new List<Profile>();
        this.ProfileDivs = new List<ProfileDiv>();
        this.ProfileDepts = new List<ProfileDept>();
    }

    #endregion

    #region Entity properties and validation attributes

    [Key]
    public long UserId { get; set; }

    public long PclientId { get; set; }

    public string UserName { get; set; }

    public string UserDescription { get; set; }

    public long? EmpId { get; set; }

    public string MustChangePassword { get; set; }

    public long? FailedLogins { get; set; }

    public DateTime? LastLogin { get; set; }

    public long? SequenceNumber { get; set; }

    public string AllDivs { get; set; }

    public string AllDepts { get; set; }

    public string UserRole { get; set; }

    public DateTime? BeginSupport { get; set; }

    public DateTime? EndSupport { get; set; }

    public string OneTimeAccess { get; set; }

    public long? ClonedFromUser { get; set; }

    public string Email { get; set; }

    public string ResetEmail { get; set; }

    public DateTime? ResetTimeout { get; set; }

    public long? ChallengeFailures { get; set; }

    public string PermUserRole { get; set; }

    public DateTime? PasswordChangedDate { get; set; }

    public virtual ICollection<Profile> Profiles { get; set; }

    public virtual ICollection<ProfileDiv> ProfileDivs { get; set; }

    public virtual ICollection<ProfileDept> ProfileDepts { get; set; }

    public virtual WorkSession WorkSession { get; set; }

}

模型构建器类是：

public class User_Map : EntityTypeConfiguration<User>
{
    public User_Map()
    {
        this.ToTable("USERS");

        this.HasKey(t => new { t.UserId });

        this.Property(t => t.UserId)
            .HasColumnName("USER_ID")
            .HasDatabaseGeneratedOption(DatabaseGeneratedOption.None)
            .IsRequired();

        this.Property(t => t.UserName)
            .HasColumnName("USERNAME")
            .IsRequired()
            .HasMaxLength(25);

        this.Property(t => t.PclientId)
            .HasColumnName("PCLIENT_ID");

        this.Property(t => t.EmpId)
            .HasColumnName("EMP_ID");

        this.Property(t => t.MustChangePassword)
            .HasColumnName("MUST_CHANGE_PASSWORD")
            .HasMaxLength(1);

        this.Property(t => t.UserDescription)
            .HasColumnName("USER_DESCRIPTION")
            .HasMaxLength(80);

        this.Property(t => t.FailedLogins)
            .HasColumnName("FAILED_LOGINS");

        this.Property(t => t.LastLogin)
            .HasColumnName("LAST_LOGIN");

        this.Property(t => t.SequenceNumber)
            .HasColumnName("SEQUENCE_NUMBER");

        this.Property(t => t.AllDivs)
            .HasColumnName("ALL_DIVS")
            .HasMaxLength(1);

        this.Property(t => t.AllDepts)
            .HasColumnName("ALL_DEPTS")
            .HasMaxLength(1);

        this.Property(t => t.UserRole)
            .HasColumnName("USER_ROLE")
            .HasMaxLength(2);

        this.Property(t => t.BeginSupport)
            .HasColumnName("BEGIN_SUPPORT");

        this.Property(t => t.EndSupport)
            .HasColumnName("END_SUPPORT");

        this.Property(t => t.OneTimeAccess)
            .HasColumnName("ONE_TIME_ACCESS")
            .HasMaxLength(1);

        this.Property(t => t.ClonedFromUser)
            .HasColumnName("CLONED_FROM_USER");

        this.Property(t => t.Email)
            .HasColumnName("EMAIL")
            .HasMaxLength(60);

        this.Property(t => t.ResetEmail)
            .HasColumnName("RESET_EMAIL")
            .HasMaxLength(60);

        this.Property(t => t.ResetTimeout)
            .HasColumnName("RESET_TIMEOUT");

        this.Property(t => t.ChallengeFailures)
            .HasColumnName("CHALLENGE_FAILURES");

        this.Property(t => t.PermUserRole)
            .HasColumnName("PERM_USER_ROLE")
            .HasMaxLength(2);

        this.Property(t => t.PasswordChangedDate)
            .HasColumnName("PASSWORD_CHANGED_DATE");

        this.HasOptional(t => t.WorkSession)
            .WithRequired(t => t.User);

        // TODO: This is syntactically correct but model blows up!

        this.HasMany(t => t.Profiles)
            .WithRequired(t => t.User)
            .HasForeignKey(t => t.UserId);

    }
}

当模型构建器类的构造函数执行时,我在上面的行上(注释后)抛出以下异常：

The expression 't => t.User' is not a valid property expression. 
The expression should represent a property: C#: 't => t.MyProperty'  
VB.Net: 'Function(t) t.MyProperty'.

Profiles实体非常简单：

[Table("PROFILE")]
public class Profile : IPEntity
{
    [Key, Column(Order = 0)]
    [ForeignKey("UserId")]
    public long UserId { get; set; }

    [Key, Column(Order = 1)]
    public string FunctionalArea { get; set; }

    public int RightsId { get; set; }

    public User User;

}

我一直在打这两天或三天,如果有人能发现我的错误,我会非常感激！

谢谢,
彼得

更新：我通过阅读this post找到了一个骨头错误,因为我已经宣布某个字段而不是属性…但现在我得到了一个我不明白的异常：

The navigation property 'UserId' is not a declared property on type 'Profile'. 
Verify that it has not been explicitly excluded from the model and that 
it is a valid navigation property.

这让我感到困惑,因为UserId是Profile上声明的属性……？

第二次更新：

我理解异常,但(因为没有内部异常细节)无法确定它的来源.我将User_map类更改为包括：

        this.HasMany(t => t.Profiles)
            .WithRequired(t => t.User)
            .HasForeignKey(t => t.UserId)
            .WillCascadeOnDelete(false);

和要包含的Profile_map类：

        this.HasRequired(t => t.User)
            .WithMany()
            .HasForeignKey(t => t.UserId)
            .WillCascadeOnDelete(false);

由于我必须使用现有的数据库,我坚持使用属性“UserId”作为两个表中的外键(在User表中,它是Profiles表的外键,在Profiles表中它是User表的外键.)我添加了.WillCascadeOnDelete(false)以防万一存在某种循环问题.就像我说的那样,我无法确定哪个映射正在吹嘘,对两个构造函数的调用都会毫无例外地传递,只有当上下文中的OnModelCreating的覆盖退出时才抛出异常.这是覆盖：

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {

        var mbProfile = new Profile_map();
        modelBuilder.Configurations.Add(mbProfile);

        var mbUser = new User_Map();
        modelBuilder.Configurations.Add(mbUser);

        base.OnModelCreating(modelBuilder);
    }

我知道我还是EF的新手,但是我找不到问题(好吧,还是还没有……)

再次感谢.

解决方法:

public User User;

应该是一个属性而不是一个字段 – 像所有其他人一样:)

public User User { get; set; }

使用虚拟优选(允许延迟加载),因为您已将所有导航属性标记为虚拟.

编辑有关更新的信息

该例外讨论导航属性UserId并抱怨它不是“有效的导航属性”.实际上它不是有效的导航属性.该异常表示您可能在WithRequired方法中使用了UserId(而不是User).你应该仔细看看.

标签：c,entity-framework,code-first
来源： https://codeday.me/bug/20190713/1454529.html