Question

请帮我解决这个问题。我已经坐了2天了，不知道我哪里做错了。我在下面看过这些文章：

但我没有解决我的问题所以我终于问了这个问题。以下是我的完整课程，以便您可以复制该问题。

Movie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
    }

Category实体

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");

    }
}

以及将Movie_Category映射到Movie的{{1}}，因为它是Category关系

Many-to-Many

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); } }继承自MovieShopContext

DbContext

所以在我的public class MovieShopContext : DbContext { public DbSet<Movie> MovieList { get; set; } public DbSet<Category> CategoryList { get; set; } public DbSet<Movie_Category_Map> MovieCategory { get; set; } static MovieShopContext() { Database.SetInitializer<MovieShopContext>(null); } public MovieShopContext() : base(@"Data Source=Newbie;Initial Catalog=SampleDB;Integrated Security=True;") { } protected override void OnModelCreating(DbModelBuilder modelBuilder) { //modelBuilder.Conventions.Remove<PluralizingTableNameConvention>(); modelBuilder.Configurations.Add(new MovieMap()); modelBuilder.Configurations.Add(new CategoryMap()); modelBuilder.Configurations.Add(new Movie_Category_Map()); } }中，我有这个代码：我删除了try-catch块

Data Access Layer

当我尝试运行代码时，它会在线停止

using (MovieShopContext _db = new MovieShopContext())
{
    Movie _movie = new Movie();
    _movie.MovieID = "M-1212-001";
    _movie.MovieName = "Book of Riddles";
    _movie.YearReleased = 2001;

    _db.MovieList.Add(_movie);  // stops here

    _db.SaveChanges();
    MessageBox.Show("Action Completed!", "Success", MessageBoxButtons.OK, MessageBoxIcon.Information);
}

并抛出此异常消息，

在模型生成期间检测到一个或多个验证错误：

\ tSystem.Data.Entity.Edm.EdmEntityType :: EntityType   'Movie_Category_Map'没有定义键。为此定义密钥   的EntityType。

\ tSystem.Data.Entity.Edm.EdmEntitySet：EntityType：EntitySet   'MovieCategory'基于没有键的'Movie_Category_Map'类型   定义

据我所知，在_db.MovieList.Add(_movie);配置中，我已经设置了主键，

Movie_Category_Map

你能指出我哪里做错了吗？或者我在哪里错过了？

Answer 1

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

这一行给你带来了麻烦

这应该是

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

您正在将EntityTypeConfiguration添加为实体，因此它正在为密钥（当前不存在密钥）进行呼叫

EntityType'Movie_Category_Map'没有定义键。定义此EntityType的键

1 个答案: