Question

我正在尝试为数据实体启用迁移：在程序包管理器控制台中：

Enable-Migrations -ProjectName Vidly -ContextTypeName Vidly.Models.MyDBContext

我明白了：

Code First Migrations enabled for project Vidly.

然后

add-migration 'InitialModel'

我得到：＆＃34;该项目＆＃39; Vidly＆＃39;无法建立。＆＃34;

我的Configuration.cs：

namespace Vidly.Migrations
{
    using System;
    using System.Data.Entity;
    using System.Data.Entity.Migrations;
    using System.Linq;

    internal sealed class Configuration : DbMigrationsConfiguration<Vidly.Models.MyDBContext>
    {
        public Configuration()
        {
            AutomaticMigrationsEnabled = false;
        }

        protected override void Seed(Vidly.Models.MyDBContext context)
        {
            //  This method will be called after migrating to the latest version.

            //  You can use the DbSet<T>.AddOrUpdate() helper extension method 
            //  to avoid creating duplicate seed data.
        }
    }
}

我的MyDBContext.cs是

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
namespace Vidly.Models
{
    public class MyDBContext
    {
        public DbSet<Customer> Customers { get; set; } // My domain models
        public DbSet<Movie> Movies { get; set; }// My domain models
    }
}

错误消息是：

错误CS0311：类型＆＃39; Vidly.Models.MyDBContext＆＃39;不能用作类型参数＆＃39; TContext＆＃39;在泛型类型或方法中＆＃39; DbMigrationsConfiguration＆＃39 ;.没有隐含的参考转换自＆＃39; Vidly.Models.MyDBContext＆＃39;至＆＃39; System.Data.Entity.DbContext＆＃39;

似乎我不能在Configuration.cs中使用MyDBContext作为类型超类。请帮忙。感谢。

Answer 1

您缺少实施DbContext。

更改并尝试：

public class MyDBContext:DBContext
    {
        public  MyDBContext() : base("ConnectionStringName")
        {           
        }
        public DbSet<Customer> Customers { get; set; } // My domain models
        public DbSet<Movie> Movies { get; set; }// My domain models
    }

Answer 2

你在这里缺少一些事情。

继承DBContext
构造函数，用于传递

使用以下代码段。注意：将VidlyDBConnectionString替换为您的连接字符串名称

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Data.Entity;
    namespace Vidly.Models
    {
        public class MyDBContext :DbContext
         {

            public MyDBContext():base("name=VidlyDBConnectionString")
            {
             }
            public DbSet<Customer> Customers { get; set; } // My domain models
            public DbSet<Movie> Movies { get; set; }// My domain models


        }
    }

Answer 3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
namespace Vidly.Models;
   {
        public class MyDBContext :DbContext
         {
            public DbSet<Customer> Customers { get; set; } // My domain models
            public DbSet<Movie> Movies { get; set; } // My domain models
         }

   }

ASP.NET MVC添加迁移。项目未能建成

3 个答案: