Hello World dotnet 核心示例不工作

Question

我是运行 Visual Studio 并尝试了 dotnet 核心的 Hello World 控制台示例。

PS d:\test> dotnet nuget list source
Registered Sources:
  1.  Microsoft Visual Studio Offline Packages [Enabled]
      C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\
  3.  Package source 1 [Enabled]
      C:\Program Files\dotnet\packs
  4.  Package source 2 [Enabled]
      C:\Program Files\dotnet\sdk\NuGetFallbackFolder

PS d:\test> dotnet --info
.NET Core SDK (reflecting any global.json):
 Version:   3.1.300
 Commit:    b2475c1295

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.18362
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk.1.300\

Host (useful for support):
  Version: 3.1.4
  Commit:  0c2e69caa6

.NET Core SDKs installed:
  2.1.514 [C:\Program Files\dotnet\sdk]
  3.1.300 [C:\Program Files\dotnet\sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.All 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.18 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download

该示例给出了找不到包的错误：

PS d:\test> dotnet new console --force
The template "Console Application" was created successfully.

Processing post-creation actions...
Running 'dotnet restore' on d:\test\test.csproj...
  Determining projects to restore...
d:\test\test.csproj : error NU1101: Unable to find package Microsoft.AspNetCore.App.Ref. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packages, Package source, Package source 1, Package source 2
  Failed to restore d:\test\test.csproj (in 402 ms).

软件包位于：C:\Program Files\dotnet\packs\Microsoft.AspNetCore.App.Ref.1.3 另外，如果我尝试将目标框架更改为 2.1，一切正常。

由 dotnet 命令行创建的默认 .csproj 文件。

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

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>netcoreapp3.1</TargetFramework>
  </PropertyGroup>

</Project>

有什么我遗漏的吗？

编辑：运行 clean

后的输出

PS d:\test> dotnet clean Microsoft (R) 构建引擎版本 16.6.0

+5ff7b0c9e for .NET Core
Copyright (C) Microsoft Corporation. All rights reserved.

Build started 5/30/2020 6:01:58 PM.

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:01.71
PS d:\test> dotnet run
d:\test\test.csproj : error NU1101: Unable to find package Microsoft.AspNetCore.App.Ref. No packages exist with this id in source(s): Microsoft Visual Studio Offline Packages, Package source, Package source 1, Package source 2

The build failed. Fix the build errors and run again.

如果我只是更改 'netcore3.1' => 'netcore2.1' 一切正常。

Answer 1

谢谢大家的建议。

我想通了这个问题。我的 nuget 源列表没有以下内容，因此工具从未在线尝试过包。

https://api.nuget.org/v3/index.json

Hello World dotnet 核心示例不工作

Hello World dotnet core example not working

c#

.net-core

visual-studio-code

.net-core-3.1

asp.net-core-3.1