C# VS2017的.net Core1.0项目在版本升级为2.0后找不到程序集的处理办法

最近不小心升级了VS2017，然后原来的.net web core1.0的项目是引用了DataBaseLib的程序集，如图  ，升级之后安装了2.0的框架，发现项目就报错了，，这个是还是之后报的错误，第一个错误是Unable to find the library 'DataBase.dll',也就是找不到所引用的程序集的位置。借助同事以及stackoverflow等问答网站，整理的解决办法如下：

修改startup.cs中的代码文件：

原来的代码:

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;

 namespace OneStop
 {
     public class Startup
     {
         public Startup(IHostingEnvironment env)
         {
             var builder = new ConfigurationBuilder()
                 .SetBasePath(env.ContentRootPath)
                 .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                 .AddEnvironmentVariables();
             Configuration = builder.Build();
         }

         public IConfigurationRoot Configuration { get; }

         // This method gets called by the runtime. Use this method to add services to the container.
         public void ConfigureServices(IServiceCollection services)
         {
             // Add framework services.
             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)
         {
             loggerFactory.AddConsole(Configuration.GetSection("Logging"));
             loggerFactory.AddDebug();

             if (env.IsDevelopment())
             {
                 app.UseDeveloperExceptionPage();
                 app.UseBrowserLink();
             }
             else
             {
                 app.UseExceptionHandler("/Home/Error");
             }

             app.UseStaticFiles();

             app.UseMvc(routes =>
             {
                 routes.MapRoute(
                     name: "default",
                     template: "{controller=Home}/{action=Index}/{id?}");
             });
         }
     }
 }

处理之后的代码：

 using DataBaseLib;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.DotNet.PlatformAbstractions;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyModel;
 using Microsoft.Extensions.DependencyModel.Resolution;
 using Microsoft.Extensions.Logging;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Serialization;
 using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Reflection;

 namespace Assemble
 {
     public class Startup
     {
         public Startup(IHostingEnvironment env)
         {
             var builder = new ConfigurationBuilder()
                 .SetBasePath(env.ContentRootPath)
                 .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                 .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                 .AddEnvironmentVariables();
             Configuration = builder.Build();
         }

         public IConfigurationRoot Configuration { get; }

         // This method gets called by the runtime. Use this method to add services to the container.
         public void ConfigureServices(IServiceCollection services)
         {

             Initialize.ConfigureServices(services);
             // Add framework services.

             var mvcBuilder = services.AddMvc();
             new MvcConfiguration().ConfigureMvc(mvcBuilder);

         }

         public class MvcConfiguration : IDesignTimeMvcBuilderConfiguration
         {
             private class DirectReferenceAssemblyResolver : ICompilationAssemblyResolver
             {
                 public bool TryResolveAssemblyPaths(CompilationLibrary library, List<string> assemblies)
                 {
                     if (!string.Equals(library.Type, "reference", StringComparison.OrdinalIgnoreCase))
                     {
                         return false;
                     }

                     var paths = new List<string>();

                     foreach (var assembly in library.Assemblies)
                     {
                         var path = Path.Combine(ApplicationEnvironment.ApplicationBasePath, assembly);

                         if (!File.Exists(path))
                         {
                             return false;
                         }

                         paths.Add(path);
                     }

                     assemblies.AddRange(paths);

                     return true;
                 }
             }

             public void ConfigureMvc(IMvcBuilder builder)
             {
                 // .NET Core SDK v1 does not pick up reference assemblies so
                 // they have to be added for Razor manually. Resolved for
                 // SDK v2 by https://github.com/dotnet/sdk/pull/876 OR SO WE THOUGHT
                 /*builder.AddRazorOptions(razor =>
                 {
                 razor.AdditionalCompilationReferences.Add(
                 MetadataReference.CreateFromFile(
                 typeof(PdfHttpHandler).Assembly.Location));
                 });*/

                 // .NET Core SDK v2 does not resolve reference assemblies‘ paths
                 // at all, so we have to hack around with reflection
                 typeof(CompilationLibrary)
                 .GetTypeInfo()
                 .GetDeclaredField("<DefaultResolver>k__BackingField")
                 .SetValue(null, new CompositeCompilationAssemblyResolver(new ICompilationAssemblyResolver[]
                 {
                     new DirectReferenceAssemblyResolver(),
                     new AppBaseCompilationAssemblyResolver(),
                     new ReferenceAssemblyPathResolver(),
                     new PackageCompilationAssemblyResolver(),
                 }));
             }
         }

         // 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)
         {
             loggerFactory.AddConsole(Configuration.GetSection("Logging"));
             loggerFactory.AddDebug();

             if (env.IsDevelopment())
             {
                 app.UseDeveloperExceptionPage();
                 app.UseBrowserLink();
             }
             else
             {
                 app.UseExceptionHandler("/Home/Error");
             }

             app.UseStaticFiles();

             app.UseMvc(routes =>
             {
                 routes.MapRoute(
                     name: "default",
                     template: "{controller=Solution}/{action=Index}/{id?}");
             });
         }
     }

 }

希望能对大家有所帮助！