建立解决方案时VS2017 Project回退框架错误

Question

我有一个.NET Core解决方案，在构建时会导致以下错误-它最初指向.NET Core 2.0，现在指向.NET Core 2.1，此后出现此错误。

我试图搜索互联网，但找不到遇到相同问题的人。

下面附有错误：

下面的项目文件

 <Project Sdk="Microsoft.NET.Sdk.Web">
    <PropertyGroup Label="Globals">
      <SccProjectName>SAK</SccProjectName>
      <SccProvider>SAK</SccProvider>
      <SccAuxPath>SAK</SccAuxPath>
      <SccLocalPath>SAK</SccLocalPath>
    </PropertyGroup>

    <PropertyGroup>
    <TargetFramework>netcoreapp2.1</TargetFramework>
    <AssetTargetFallback>%3bnet461%3bportable-net45+win8</AssetTargetFallback>
   </PropertyGroup>

    <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">
      <PlatformTarget>AnyCPU</PlatformTarget>
    </PropertyGroup>

    <ItemGroup>
     <Compile Remove="Controllers\TestController.cs" />
     <Compile Remove="Controllers\ValuesController.cs" />
    </ItemGroup>

    <ItemGroup>
    <Folder Include="wwwroot\" />
    </ItemGroup>

    <ItemGroup>
    <PackageReference Include="EvoHtmlToPdf_NetCore_Client" Version="7.5.0" 
    />
    <PackageReference Include="Kendo.Mvc" Version="2016.2.616" />
    <PackageReference Include="Microsoft.AspNetCore.All" Version="2.1.5" />
    <PackageReference Include="Microsoft.AspNetCore.Authentication" 
     Version="2.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Authentication.JwtBearer" Version="2.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Authorization" Version="2.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Authorization.Policy" Version="2.1.2" />
    <PackageReference Include="Microsoft.AspNetCore.Identity" Version="2.1.3" />
    <PackageReference Include="Microsoft.AspNetCore.Identity.EntityFrameworkCore" Version="2.1.3" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Binder" Version="2.1.1" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="2.1.1" />
    <PackageReference Include="Microsoft.Extensions.Options" Version="2.1.1" />
    <PackageReference Include="Microsoft.IdentityModel.Tokens" Version="5.2.4" />
    <PackageReference Include="Mime" Version="3.0.1" />
    <PackageReference Include="System.IO.FileSystem" Version="4.3.0" />
  </ItemGroup>

  <ItemGroup>
    <DotNetCliToolReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Tools" Version="2.0.0-preview2-final" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\TEST\DataLayer.csproj" />
  </ItemGroup>

  <ItemGroup>
    <Content Update="appsettings.json">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </Content>
  </ItemGroup>

  <ItemGroup>
    <None Update="AppSettings.cs.d.ts">
      <DependentUpon>AppSettings.cs</DependentUpon>
    </None>

Answer 1

删除此行将其修复-感谢Jon和Camilo

<AssetTargetFallback>%3bnet461%3bportable-net45+win8</AssetTargetFallback>