目前正在学习2018年初的课程。
在程序包管理器控制台中运行添加迁移初始后
这是我的错误消息;
无法创建类型为"AppDbContext"的对象。将"IDesignTimeDbContextFactory"的实现添加到项目中,或参阅 https://go.microsoft.com/fwlink/?linkid=851728 了解设计时支持的其他模式。
该链接说要添加...
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Design;
using Microsoft.EntityFrameworkCore.Infrastructure;
namespace MyProject
{
public class BloggingContextFactory : IDesignTimeDbContextFactory<BloggingContext>
{
public BloggingContext CreateDbContext(string[] args)
{
var optionsBuilder = new DbContextOptionsBuilder<BloggingContext>();
optionsBuilder.UseSqlite("Data Source=blog.db");
return new BloggingContext(optionsBuilder.Options);
}
}
}
到我的创业.cs...
这是我的创业班
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using BethanysPieShop.Models;
using Microsoft.Extensions.Configuration;
using Microsoft.EntityFrameworkCore;
using WebApplication5.Models;
namespace BethanysPieShop
{
public class Startup
{
private IConfigurationRoot _configurationRoot;
public Startup(IHostingEnvironment hostingEnvironment)
{
_configurationRoot = new ConfigurationBuilder()
.SetBasePath(hostingEnvironment.ContentRootPath)
.AddJsonFile("appsettings.json")
.Build();
}
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<AppDbContext>(options =>
options.UseSqlServer(_configurationRoot.GetConnectionString("DefaultConnection")));
services.AddTransient<ICategoryRepository, CategoryRepository>();
services.AddTransient<IPieRepository, PieRepository>();
services.AddMvc();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
app.UseDeveloperExceptionPage();
app.UseStatusCodePages();
app.UseStaticFiles();
app.UseMvcWithDefaultRoute();
}
}
}
我正在使用实体框架核心工具 2.1.2
AppDbContext.cs
using BethanysPieShop.Models;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace WebApplication5.Models
{
public class AppDbContext : DbContext
{
public AppDbContext(DbContextOptions<AppDbContext> options) : base(options)
{
}
public DbSet<Category> Categories { get; set; }
public DbSet<Pie> Pies { get; set; }
public class DbSet
{
}
}
}
我在代码中的什么位置/位置实现他们的代码?
我应该更改哪些变量?
记得这个问题是由于您没有使用正确的WebHostBuilder方法名称而引起的 请参阅此 github 问题
public class Program
{
public static void Main(string[] args)
{
BuildWebHost(args).Run();
}
//.Net-core relies on Duck Typing during migrations and scaffolding
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseStartup<Startup>()
.Build();
}
试着把这个:
services.AddScoped(typeof(IDesignTimeDbContextFactory<BloggingContext>), typeof(BloggingContextFactory));
在 Startup.cs 中,方法配置服务,位于服务下方。AddTransient <IPieRepository,>();
我希望你觉得它有用