这个练习的内容
在本文中，我们将研究这两个用例：
主应用程序静态引用的RCL
由主应用程序动态加载的RCL。
两个rcl都包含静态文件，即javasript和css文件。
我们将使用Asp.Net核心MVC Web应用程序和两个rcl。
为开始创建Asp.Net核心MVC Web应用程序，并将其命名为WebApp。

参考RCL
按照文档提供的说明创建RCL。
将RCL命名为StaticRCL。我们稍后再看为什么名字很重要。
从项目中删除所有文件和文件夹，并添加三个新文件夹、Controller、Views和wwwroot。
在Controllers文件夹中创建控制器类。

 public class LibController : Controller
 {
        [Route("/static")]
        public IActionResult Index()
        {
            return View();
        }
 }

在Views文件夹中创建Lib文件夹。添加Index.cshtml查看文件。

 <script src="~/_content/StaticRCL/js/script.js"></script>

    <div>
        <strong>STATICALLY</strong> referenced Razor Class Library
    </div>

    <div>
        <button onclick="StaticRCL_ShowMessage();">Click Me!</button>
    </div>

 function StaticRCL_ShowMessage() {
        alert('Hi from Statically refernced Razor Class Library javascript');
    }

Controller

public class LibDynamicController : Controller
{
        [Route("/dynamic")]
        public IActionResult Index()
        {
            return View();
        }
}

 <script src="js/script.js"></script>

<div>
    <strong>DYNAMICALLY</strong> loaded Razor Class Library
</div>

<div>
    <button onclick="DynamicRCL_ShowMessage();">Click Me!</button>
</div>

function DynamicRCL_ShowMessage() {
    alert('Hi from Dynamically loaded Razor Class Library javascript');
}

<Project Sdk="Microsoft.NET.Sdk.Razor">

  <PropertyGroup>
    <TargetFramework>netcoreapp3.1</TargetFramework>
    <AddRazorSupportForMvc>true</AddRazorSupportForMvc>
    <AssemblyName>rcl_DynamicRCL</AssemblyName>
    <CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>     
    <GenerateEmbeddedFilesManifest>true</GenerateEmbeddedFilesManifest>
  </PropertyGroup>

  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
    <OutputPath>..\WebApp\bin\Debug\</OutputPath>
  </PropertyGroup>

  <ItemGroup>
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="Microsoft.Extensions.FileProviders.Embedded" Version="3.1.0" />
  </ItemGroup> 
    
   <ItemGroup>
      <EmbeddedResource Include="wwwroot\**\*" />
   </ItemGroup>

</Project>

@{
    ViewData["Title"] = "Home Page";
}

<div class="text-center">
    <h1 class="display-4">Welcome</h1>
    <div><a href="/static">Statically referenced Razor Class Library View</a></div>
    <div><a href="/dynamic">Dynamically loaded Razor Class Library View</a></div>
</div>

public void ConfigureServices(IServiceCollection services)
{
        services.AddControllersWithViews().
            ConfigureApplicationPartManager((PartManager) => {
                ConfigureStaticLibraries(PartManager);  // static RCLs
                LoadDynamicLibraries(PartManager);      // dynamic RCLs
            });
}

void ConfigureStaticLibraries(ApplicationPartManager PartManager)
{
        Assembly Assembly = typeof(StaticRCL.Controllers.LibController).Assembly;  
        ApplicationPart ApplicationPart = new AssemblyPart(Assembly);

        PartManager.ApplicationParts.Add(ApplicationPart);
}

<script src="~/_content/StaticRCL/js/script.js"></script>

 public class LibraryLoadContext: AssemblyLoadContext
    {
        private AssemblyDependencyResolver fResolver;

        public LibraryLoadContext(string BinFolder)
        {
            fResolver = new AssemblyDependencyResolver(BinFolder);
        }

        protected override Assembly Load(AssemblyName assemblyName)
        {
            string assemblyPath = fResolver.ResolveAssemblyToPath(assemblyName);
            if (assemblyPath != null)
            {
                return LoadFromAssemblyPath(assemblyPath);
            }

            return null;
        }

        protected override IntPtr LoadUnmanagedDll(string unmanagedDllName)
        {
            string FilePath = fResolver.ResolveUnmanagedDllToPath(unmanagedDllName);
            if (FilePath != null)
            {
                return LoadUnmanagedDllFromPath(FilePath);
            }

            return IntPtr.Zero;
        }
    }

 void LoadDynamicLibraries(ApplicationPartManager PartManager)
    {
        // get the output folder of this application
        string BinFolder = this.GetType().Assembly.ManifestModule.FullyQualifiedName;
        BinFolder = Path.GetDirectoryName(BinFolder);

        // get the full filepath of any dll starting with the rcl_ prefix
        string Prefix = "rcl_";
        string SearchPattern = $"{Prefix}*.dll";   
        string[] LibraryPaths = Directory.GetFiles(BinFolder, SearchPattern);

        if (LibraryPaths != null && LibraryPaths.Length > 0)
        {
            // create the load context
            LibraryLoadContext LoadContext = new LibraryLoadContext(BinFolder);

            Assembly Assembly;
            ApplicationPart ApplicationPart;
            foreach (string LibraryPath in LibraryPaths)
            {
                // load each assembly using its filepath
                Assembly = LoadContext.LoadFromAssemblyPath(LibraryPath);

                // create an application part for that assembly
                ApplicationPart = LibraryPath.EndsWith(".Views.dll") ? new CompiledRazorAssemblyPart(Assembly) as ApplicationPart : new AssemblyPart(Assembly);

                // register the application part
                PartManager.ApplicationParts.Add(ApplicationPart);

                // if it is NOT the *.Views.dll add it to a list for later use
                if (!LibraryPath.EndsWith(".Views.dll"))
                    DynamicallyLoadedLibraries.Add(Assembly);
            } 
        }
    }

 void RegisterDynamicLibariesStaticFiles(IWebHostEnvironment env)
    {
        IFileProvider FileProvider;
        foreach (Assembly A in DynamicallyLoadedLibraries)
        {
            // create a "web root" file provider for the embedded static files found on wwwroot folder       
            FileProvider = new ManifestEmbeddedFileProvider(A, "wwwroot");

            // register a new composite provider containing
            // the old web root file provider
            // and the new one we just created
            env.WebRootFileProvider = new CompositeFileProvider(env.WebRootFileProvider, FileProvider); 
        }
    }

 app.UseHttpsRedirection();

    // register file providers for the dynamically loaded libraries
    if (DynamicallyLoadedLibraries.Count > 0)
        RegisterDynamicLibariesStaticFiles(env);

    app.UseStaticFiles();

这是DynamicRCL项目中的Index.cshtml做的，为了使用javascript文件

<script src="js/script.js"></script>

这里没有使用_content/{LIBRARY NAME}/方案。我们只使用js文件夹，因为我们已经将DynamicRCL程序集的wwwroot文件夹注册为web根文件夹。

测试在：
Windows 10
Asp.Net  Core 3.1
Microsoft Visual Studio 2019预览版，版本16.9.0预览版5.0