如何添加 IDesignTimeDbContextFactory 的实现以将迁移添加到 .Net core 2.0 应用程序？

Question

我正在尝试运行从 .NET Core 2.0 MVC 应用程序的包管理器控制台添加迁移 InitialCreate 命令。查看所有可能的来源后仍然无法解决问题，错误描述为：

PM> Add-Migration InitialCreate

An error occurred while calling method 'BuildWebHost' on class 'Program'. Continuing without the application service provider. Error: Method not found: 'System.Collections.Generic.Dictionary2<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 key, Func2 valueFactory) at Microsoft.EntityFrameworkCore.DbContext..ctor(DbContextOptions options) at MvcMovie.Models.MvcMovieContext..ctor(DbContextOptions1 options) in C:\Users\Neha\source\repos\MvcMovie\MvcMovie\Data\MvcMovieContext.cs:line 12 at MvcMovie.ToDoContextFactory.CreateDbContext(String[] args) in C:\Users\Neha\source\repos\MvcMovie\MvcMovie\ToDoContextFactory.cs:line 17 at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(Func1 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() at 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

的实现

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);
    }
}

有人可以通过描述性的分步过程帮助我将模型和 Entity Framework 工具添加到 .NET Core2.0 应用程序。

Answer 1

有同样的问题。它发生在我将 Microsoft.AspNetCore.All 从 2.0.0-preview2-final 更新到 2.0.0 之后。猜猜它失败的原因是我安装了 .NET Core Preview 2 运行时。

EFCore 也更新了。所以请确保你有相同的 nuget 和运行时版本

更新： 现在发布了 .NET Core 运行时和 SDK 2.0 https://www.microsoft.com/net/download/core。安装后你可以安全地将你的包更新到 2.0.0

Answer 2

您需要更改您的 class 程序

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

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

此 class changed 与 dotnet 核心 2.0.0

Answer 3

我遇到了同样的问题

我的解决方案包含一个控制台应用程序和一个包含 dbcontext 代码的 api 应用程序。

我已将启动项目设置为控制台应用程序。当我将启动项目更改为 api 应用程序时，错误消失了。

如何添加 IDesignTimeDbContextFactory 的实现以将迁移添加到 .Net core 2.0 应用程序？

How to add an implementation of IDesignTimeDbContextFactory to add migration to .Net core 2.0 application?

asp.net

asp.net-mvc

entity-framework

asp.net-core-2.0