构建解决方案时VS2017项目回退框架错误答案

【问题标题】：VS2017 Project fallback framework error when building solution构建解决方案时VS2017项目回退框架错误
【发布时间】：2019-04-07 13:19:17
【问题描述】：

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

我尝试在互联网上搜索，但找不到遇到同样问题的人。

错误附在下面：

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>

【问题讨论】：

现在很少需要后备框架，尤其是基于 PCL 的框架 - 你确定你需要它吗？你能发布你的完整项目文件吗？
即使你需要它，开头的;也不应该在那里
@JonSkeet 看起来是这一行 %3bnet461%3bportable-net45+win8
正如 Jon 所说，如果您不需要该行，请将其删除。正如我所说，如果您需要该行，请从字符串的开头删除 %3b

标签： c# msbuild .net-core visual-studio-2017

【解决方案1】：

删除这条线修复了它 - 感谢 Jon 和 Camilo

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

【讨论】：