c# - 在 ASP.NET Core 3 的类库中创建 TagHelper

Question

如何使用对 ASP.NET Core 3 的更改在单独的类库中创建 TagHelper 类？

在 ASP.NET Core 1.x 和 2.x 中，您可以仅引用 NuGet 包 Microsoft.AspNetCore.Razor 以允许您的类派生自 Microsoft.AspNetCore。 Razor.TagHelpers.TagHelper.

在ASP.NET Core 3.x中，似乎只有一个名为Microsoft.AspNetCore.App的大包，在NuGet上找不到。

该解决方案应支持在 ASP.NET Core 3 和更早版本 中使用包含的 TagHelper 类。

Answer 1

看看Migrate from ASP.NET Core 2.2 to 3.0 .

它解释了仅引用 Microsoft.NET.Sdk.Razor 的项目(例如您的类库)需要添加对 Microsoft.AspNetCore.App 的引用。但是，对于面向 Microsoft.NET.Sdk.Web(例如 MVC 应用程序或 WebAPI)的项目，这会自动包含在内。

引自FrameworkReference部分(第二个项目符号适用于您的项目):

Features of ASP.NET Core that were available through one of the packages listed above are available as part of the Microsoft.AspNetCore.App shared framework. The shared framework is the set of assemblies (.dll files) that are installed on the machine and includes a runtime component, and a targeting pack. For more information, see The shared framework.

• Projects that target the Microsoft.NET.Sdk.Web SDK implicitly reference the Microsoft.AspNetCore.App framework. No additional references are required for these projects:

  <Project Sdk="Microsoft.NET.Sdk.Web">
    <PropertyGroup>
      <TargetFramework>netcoreapp3.0</TargetFramework>
    </PropertyGroup>
    ...
  </Project>
  

• Projects that target Microsoft.NET.Sdk or Microsoft.NET.Sdk.Razor SDK, should add an explicit FrameworkReference to Microsoft.AspNetCore.App:

  <Project Sdk="Microsoft.NET.Sdk.Razor">
    <PropertyGroup>
      <TargetFramework>netcoreapp3.0</TargetFramework>
    </PropertyGroup>
  
    <ItemGroup>
      <FrameworkReference Include="Microsoft.AspNetCore.App" />
    </ItemGroup>
    ...
  </Project>