如何添加IDesignTimeDbContextFactory的实现以添加到.Net core 2.0应用程序的迁移？

Question

我试图从.NET Core 2.0 MVC应用程序的包管理器控制台运行Add-Migration InitialCreate命令.在查看所有可能的来源之后仍然无法解决错误描述的问题:

PM> Add-Migration InitialCreate

在类'Program'上调用方法'BuildWebHost'时发生错误.继续没有应用程序服务提供商.错误:找不到方法:C:\ Users\Neha\source\repos\MvcMovie\MvcMovie\Data\MvcMovieContext.cs中的'System.Collections.Generic.Dictionary 2<System.String,System.Object> Microsoft.Extensions.Configuration.IConfigurationBuilder.get_Properties()'. System.IO.FileLoadException: Could not load file or assembly 'System.Diagnostics.DiagnosticSource, Version=4.0.2.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) File name: 'System.Diagnostics.DiagnosticSource, Version=4.0.2.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' at Microsoft.EntityFrameworkCore.Infrastructure.EntityFrameworkServicesBuilder.TryAddCoreServices() at Microsoft.Extensions.DependencyInjection.SqlServerServiceCollectionExtensions.AddEntityFrameworkSqlServer(IServiceCollection serviceCollection) at Microsoft.EntityFrameworkCore.Infrastructure.Internal.SqlServerOptionsExtension.ApplyServices(IServiceCollection services) at Microsoft.EntityFrameworkCore.Internal.ServiceProviderCache.ApplyServices(IDbContextOptions options, ServiceCollection services) at Microsoft.EntityFrameworkCore.Internal.ServiceProviderCache.<>c__DisplayClass4_0.<GetOrAdd>b__2(Int64 k) at System.Collections.Concurrent.ConcurrentDictionary2.GetOrAdd(TKey键,Func 2 valueFactory) at Microsoft.EntityFrameworkCore.DbContext..ctor(DbContextOptions options) at MvcMovie.Models.MvcMovieContext..ctor(DbContextOptions1选项):第12行at MvcMovie.ToDoContextFactory.CreateDbContext(String [] args)位于C:\ Users\Neha\source\repos\MvcMovie\MvcMovie\ToDoContextFactory.cs:第17行,位于Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(Func 1 factory) at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(String contextType) at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType) at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_01.b__0) ()Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)

Could not load file or assembly 'System.Diagnostics.DiagnosticSource, Version=4.0.2.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

我的Program.cs看起来像:

 public class Program
{
    public static void Main(string[] args)
    {
        var host = new WebHostBuilder()
            .UseKestrel()
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseIISIntegration()
            .UseStartup<Startup>()
            .UseApplicationInsights()
            .Build();

        host.Run();
    }

    public static IWebHost BuildWebHost(string[] args) =>
        new WebHostBuilder()
        .UseKestrel()
        .UseContentRoot(Directory.GetCurrentDirectory())
        .UseIISIntegration()
        .UseStartup<Startup>()
        .Build();
}

还添加了实现

IDesignTimeDbContextFactory

public class ToDoContextFactory : IDesignTimeDbContextFactory<MvcMovieContext>
{
    public MvcMovieContext CreateDbContext(string[] args)
    {
        var builder = new DbContextOptionsBuilder<MvcMovieContext>();
        builder.UseSqlServer("Server=(local);Database=MvcMovieContext;Trusted_Connection=True;MultipleActiveResultSets=true");
        return new MvcMovieContext(builder.Options);
    }
}

有人可以帮助我使用描述性的逐步过程将模型和实体框架工具添加到.NET Core2.0应用程序.

Answer 1

你需要改变你的课程

public class Program
{
    public static void Main(string[] args)
    {
        BuildWebHost(args).Run();
    }

    public static IWebHost BuildWebHost(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseStartup<Startup>()
            .Build();
}

这个类改为 dotnet core 2.0.0