C# EntityType'；电影分类地图'；没有定义键。定义此EntityType的键

请帮我解决这个问题。我已经坐了两天了，不知道哪里做错了。我在下面看到了这篇文章：

但我还没有解决我的问题，所以我终于问了这个问题。下面是我的完整课程，您可以复制该问题

电影

实体

public class Movie
{
    public Movie()
    {
        this.MovieCategoryList = new List<Movie_Category>();
    }
    public string MovieID { get; set; }
    public string MovieName { get; set; }
    public Nullable<int> YearReleased { get; set; }
    public virtual ICollection<Movie_Category> MovieCategoryList { get; set; }
}

public class MovieMap : EntityTypeConfiguration<Movie>
{
    public MovieMap()
    {
        // Primary Key
        this.HasKey(p => p.MovieID);

        // Property
        this.Property(p => p.MovieID)
            .IsRequired()
            .HasMaxLength(15);

        this.Property(p => p.MovieName)
            .IsRequired()
            .HasMaxLength(50);

        this.Property(p => p.YearReleased)
            .IsOptional();

        // Table and Column Mappings
        this.ToTable("Movie");
        this.Property(p => p.MovieID).HasColumnName("MovieID");
        this.Property(p => p.MovieName).HasColumnName("MovieName");
        this.Property(p => p.YearReleased).HasColumnName("YearReleased");

        // Relationships
    }

public class Category
{
    public Category()
    {
        this.MovieCategoryList = new List<Movie_Category>();
    }
    public string CategoryID { get; set; }
    public string CategoryName { get; set; }
    public virtual ICollection<Movie_Category> MovieCategoryList { get; set; }
}

public class CategoryMap : EntityTypeConfiguration<Category>
{
    public CategoryMap()
    {
        // Primary Key
        this.HasKey(p => p.CategoryID);

        // Property
        this.Property(p => p.CategoryID)
            .IsRequired()
            .HasMaxLength(15);

        this.Property(p => p.CategoryName)
            .IsRequired()
            .HasMaxLength(30);

        // Mappings
        this.ToTable("Category");
        this.Property(p => p.CategoryID).HasColumnName("CategoryID");
        this.Property(p => p.CategoryName).HasColumnName("CategoryName");

    }
}

以及

Movie\u Category

，它将

Movie

映射到

Category

，因为它是一种

多对多

关系

public class Movie_Category
{
    public int MovieCategoryID { get; set; }
    public string MovieID { get; set; }
    public string CategoryID { get; set; }

    public virtual Movie Movie { get; set; }
    public virtual Category Category { get; set; }
}

public class Movie_Category_Map : EntityTypeConfiguration<Movie_Category>
{
    public Movie_Category_Map()
    {
        // Primary Key
        this.HasKey(p => p.MovieCategoryID);

        // Property
        this.Property(p => p.MovieCategoryID)
            .IsRequired()
            .HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);

        this.Property(p => p.CategoryID)
            .IsRequired()
            .HasMaxLength(15);

        this.Property(p => p.MovieID)
            .IsRequired()
            .HasMaxLength(15);

        // Mappings
        this.ToTable("Movie_Category");
        this.Property(p => p.MovieCategoryID).HasColumnName("RecordID");
        this.Property(p => p.MovieID).HasColumnName("MovieID");
        this.Property(p => p.CategoryID).HasColumnName("CategoryID");

        // Relationship
        this.HasRequired(t => t.Category)
            .WithMany(t => t.MovieCategoryList)
            .HasForeignKey(p => p.CategoryID);

        this.HasRequired(t => t.Movie)
            .WithMany(t => t.MovieCategoryList)
            .HasForeignKey(p => p.MovieID);

    }
}

因此，在我的

数据访问层

中，我有以下代码：我已经删除了try-catch块

当我试图运行代码时，它会停止运行

_db.MovieList.Add(_movie);

并抛出此异常消息

在模型生成过程中检测到一个或多个验证错误：

\tSystem.Data.Entity.Edm.EdmEntityType:：EntityType “电影类别映射”未定义键。为此定义密钥 EntityType

\tSystem.Data.Entity.Edm.EdmEntitySet:EntityType:EntitySet “MovieCategory”基于没有键的类型“Movie\u Category\u Map” 定义

据我所知，在

Movie\u Category\u Map

配置中，我已经设置了一个主键

this.HasKey(p => p.MovieCategoryID);

你能告诉我哪里做错了吗？或者我在哪里丢失了？

公共DbSet MovieCategory{get；set；}
public DbSet<Movie_Category_Map> MovieCategory { get; set; }

这条线给你添麻烦了

这应该是

public DbSet<Movie_Category> MovieCategory { get; set; }

public DbSet MovieCategory{get；set；}

您正在将EntityTypeConfiguration添加为一个实体，因此它正在呼喊密钥（当然，密钥不存在）

public DbSet<Movie_Category_Map> MovieCategory { get; set; }

public DbSet<Movie_Category> MovieCategory { get; set; }