Question

我想为新闻创建类别。这将是多对多的关系。怎么做得好？我创建了两个类：

public class News
{
    public News()
    {
        this.NewsCategories = new List<NewsCategory>();
    }
    public int ID { get; set; }
    public DateTime Date { get; set; }
    public string Title { get; set; }  
    public string Text { get; set; }
    public IEnumerable<NewsCategory> NewsCategories { get; set; }
}

public class NewsCategory
{
    public NewsCategory()
    {
        this.News = new List<News>();
    }
    public int ID { get; set; }
    public string Name { get; set; }
    public IEnumerable<News> News { get; set; }
}

但EF只创建两个表...没有连接表。我也创建了自定义DbInitializer：

public class TouristGuideDBInitializer : DropCreateDatabaseAlways<TouristGuideDB>
{
    protected override void Seed(TouristGuideDB context)
    {
        base.Seed(context);
        context.NewsCategories.Add(new NewsCategory { Name = "Default" });
        context.NewsCategories.Add(new NewsCategory { Name = "Second" });
        context.News.Add(new News { Date = DateTime.Now, Text = "asasdfas fasdfa sdf asf asf", Title = "Hello world" });
        context.SaveChanges();
        var news = context.News.First();            
        var cat = context.NewsCategories.Where(r => r.Name == "Default").Single();            
        news.NewsCategories.ToList().Add(cat);
        context.SaveChanges();
    }
}

但它只添加一个新闻和两个类别......没有关系...... 如何正确地完成（关系）？

Answer 1

您需要使用ICollection<T>作为导航属性。

ASP.NET MVC3 - 实体框架：多对多关系（新闻和类别）

1 个答案: