说明
====

## 关于 共享框架
随着 .NET Core 3.0 的发布，许多 ASP.NET Core 程序集不再作为包发布到 NuGet。
相反，程序集包含在 Microsoft.AspNetCore.App 共享框架中，该框架随 .NET Core SDK 和运行时安装程序一起安装。

+ Web项目，一般自动包含 AspMicrosoft.AspNetCore.App 共享框架，即 共享框架由项目的Sdk属性（Microsoft.NET.Sdk.Web）自动引入
```xml
<Project Sdk="Microsoft.NET.Sdk.Web">
  <!--共享项目由上面Sdk类型（Microsoft.NET.Sdk.Web）自动引入-->
  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

  <ItemGroup>
    <!--Nuget包引用-->
    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="7.0.5" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.4.0" />
  </ItemGroup>

  <ItemGroup>
    <!--项目引用-->
    <ProjectReference Include="..\xx.csproj" />
  </ItemGroup>

</Project>
```
+ 类库项目等，要手动引入(无法使用nuget包的方式引入)
```xml
<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net7.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <!-- 手动引入共享框架(不指定版本，自动跟随项目版本)，多目标项目，也可以使用变量根据目标选择引入-->
	<FrameworkReference Include="Microsoft.AspNetCore.App" />
  </ItemGroup>

  <ItemGroup>
    <!--Nuget包引用-->
    <PackageReference Include="Microsoft.AspNetCore.OpenApi" Version="7.0.5" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.4.0" />
  </ItemGroup>

  <ItemGroup>
    <!--项目引用-->
    <ProjectReference Include="..\xx.csproj" />
  </ItemGroup>

</Project>
```
```xml
<!-- 多目标示例-->
<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFrameworks>netstandard2.0;netcoreapp3.0;netcoreapp3.1;net5.0;net6.0;net7.0</TargetFrameworks>
    <PackageTags>aspnetcore;authentication;security;basicauth</PackageTags>
    <Configurations>Debug;Release;CodeQL</Configurations>
  </PropertyGroup>

  <!-- netstandard2.0 版本引入老版本的包(Microsoft.AspNetCore.Authentication等) -->
  <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
    <PackageReference Include="Microsoft.AspNetCore.Authentication" Version="2.0" />
    <PackageReference Include="Microsoft.AspNetCore.Http.Abstractions" Version="2.0" />
    <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="2.0" />
  </ItemGroup>

  <!-- 高版本手动引入共享框架（Microsoft.AspNetCore.App），由共享框架引入模块 -->
  <ItemGroup Condition="'$(TargetFramework)' != 'netstandard2.0'">
    <FrameworkReference Include="Microsoft.AspNetCore.App" />
  </ItemGroup>
</Project>
```