Question

现有一个名为Northwind的数据库带有一个webform应用程序。运行应用程序时出现错误： '无效的列名称CategoryCategoryID'。谁帮帮我？提前谢谢!!

Category.cs：

public class Category
{

    public int CategoryID { get; set; }
   // public int ID { get; set; }
    public string CategoryName { get; set; }
    public string Description { get; set; }
    public byte[] Picture { get; set; }
    public virtual ICollection<Product> Products { get; set; }
}

Product.cs：

public class Product
{

    public int ProductID { get; set; }
    //public int ID { get; set; }
    public string ProductName { get; set; }
    public Decimal? UnitPrice { get; set; }
    public bool Discontinued{ get; set; }
    public virtual Category Category{ get; set; }
}

Northwind.cs

public class Northwind:   DbContext
{
    public DbSet< Product  > Products { get; set; }
    public DbSet< Category > Categorys{ get; set; }
}

Products.aspx

protected void Page_Load(object sender, EventArgs e)
{
    Northwind northwind = new Northwind();

    var products = from p in northwind.Products
    where p.Discontinued == false
    select p;

    GridView1.DataSource = products.ToList();
    GridView1.DataBind();
}

Answer 1

解决此问题的一种方法是向Product实体添加新的FK属性：

public class Product
{
    public int ProductID { get; set; }        
    public string ProductName { get; set; }
    public Decimal? UnitPrice { get; set; }
    public bool Discontinued { get; set; }
    [ForeignKey("Category")]
    public int CategoryId { get; set; }

    public virtual Category Category { get; set; }
}

EF Code第一个无效列名“CategoryCategoryID”

1 个答案: