Question

我对EF并不熟悉，只是对WebAPI一本书的示例不熟悉。

这是我得到的错误：

这是我拥有的DbContext类：

namespace SportsStore.Models
{
    public class ProductDbContext: DbContext
    {
        public ProductDbContext()
            : base("SportsStoreDb")
        {
            Database.SetInitializer<ProductDbContext>(new ProductDbInitializer());
        }

        public DbSet<Product> Products { get; set; }
        public DbSet<Order> Orders { get; set; }
        public DbSet<OrderLine> OrderLines { get; set; }
    }
}

还有一个类似这样的Initializer类：

using System.Collections.Generic;
using System.Data.Entity;

namespace SportsStore.Models
{
    public class ProductDbInitializer : DropCreateDatabaseAlways<ProductDbContext>
    {
        protected override void Seed(ProductDbContext context)
        {
            new List<Product> {
                new Product() { Name = "Kayak", Description = "A boat for one person",
                    Category = "Watersports", Price = 275m },
                new Product() { Name = "Lifejacket",
                    Description = "Protective and fashionable",
                    Category = "Watersports", Price = 48.95m },
                new Product() { Name = "Soccer Ball",
                    Description = "FIFA-approved size and weight",
                    Category = "Soccer", Price = 19.50m },
                new Product() {
                    Name = "Corner Flags",
                    Description = "Give your playing field a professional touch",
                    Category = "Soccer", Price = 34.95m },
                new Product() { Name = "Stadium",
                    Description = "Flat-packed 35,000-seat stadium",
                    Category = "Soccer", Price = 79500m },
                new Product() { Name = "Thinking Cap",
                    Description = "Improve your brain efficiency by 75%",
                    Category = "Chess", Price = 16m },
                new Product() { Name = "Unsteady Chair",
                    Description = "Secretly give your opponent a disadvantage",
                    Category = "Chess", Price = 29.95m },
                new Product() { Name = "Human Chess Board",
                    Description = "A fun game for the family",
                    Category = "Chess", Price = 75m },
                new Product() { Name = "Bling-Bling King",
                    Description = "Gold-plated, diamond-studded King",
                    Category = "Chess", Price = 1200m },
            }.ForEach(product => context.Products.Add(product));

            context.SaveChanges();

            new List<Order> {
                new Order() { Customer = "Alice Smith", TotalCost = 68.45m,
                    Lines = new List<OrderLine> {
                        new OrderLine() { ProductId = 2, Count = 2},
                        new OrderLine() { ProductId = 3, Count = 1},
                    }},
                new Order() { Customer = "Peter Jones", TotalCost = 79791m,
                    Lines = new List<OrderLine> {
                        new OrderLine() { ProductId = 5, Count = 1},
                        new OrderLine() { ProductId = 6, Count = 3},
                        new OrderLine() { ProductId = 1, Count = 3},
                   }}
            }.ForEach(order => context.Orders.Add(order));

            context.SaveChanges();
        }
    }
}

我也能够登录到SQL Server引擎的本地主机数据库。

那我应该怎么解决这个问题？

Answer 1

Ok终于自己解决了。是的，没有连接字符串。很高兴我没有去找别人重复回答的那个兔子洞。

问题出在Web中。配置以下版本为13，现在将其更改为11。

<defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
  <parameters>
    <parameter value="v11.0" />
  </parameters>
</defaultConnectionFactory>

实体框架无法连接和创建数据库

1 个答案: