NET Core 3.0在 Visual Studio 2019上没有显示

我想测试新的 Blazor 服务器端框架(又名 Razor 组件)。

我安装了 Visual Studio 2019 RC，然后在 这个官方教程之后安装了.Net Core 3.0预览版2。

安装完成后，我只能在“创建一个新的 ASP.NET 核心 Web 应用程序”页面上看到 ASP.NET Core 2.0和2.1。3.0没有出现。

我开始胡闹，试图从 这一页安装其他软件包，卸载和重新安装 VisualStudio2019，更新到。NET Core Preview 3，以不同的顺序多次安装 x64和 x86包，复制/粘贴。NetCore 二进制文件到随机文件夹等等。什么都没用。ASP.NET Core 3.0没有出现。

下面是我的 VS 在创建一个项目时的样子(黄色的消息出现在后面，是在一些软件包的混乱之后出现的，所以它不是真正的问题) :

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下面是 dotnet --list-sdks命令的输出:

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剪辑

出于某种原因，我安装了 Blazor VSIX 软件包(WebAssembly ——不完全是我想要的，但我还是安装了它) ，现在 ASP.NET Core 3.0就出现了。然而，仅仅对于 blazor 模板:

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我不明白，我是不是漏掉了什么？

98217 次浏览
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I have the same issue here after moving from Visual Studio 2019 Preview to Visual Studio 2019 RC.

This page seems to suggest that you need Preview to use .net Core 3.0 which is annoying.

https://dotnet.microsoft.com/download/dotnet-core/3.0

I looked up the difference between RC and Preview, and they pull builds from different channels (stable and preview).

The next thing I’m going to try is to go back to Preview to see if .Net Core 3.0 becomes visible again.

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最佳答案

There is an option in Tools -> Options that enables preview versions of the .NET Core SDK. In the VS Preview shipping channel, it is on (by default, and not settable). In the VS Release channel, it defaults to off and you can opt-in.

"Use Previews of the .NET Core SDK" in the Tools->Options dialog

(Note: it's disabled in the screenshot because I have a Preview build installed.)

The reason for this is to allow you to customize whether a project using a released version of .NET Core (such as 2.1, the current LTS) will use tooling from the newer not-yet-release-quality SDK.

Prior to 16.1, this option was located on the Tools -> Options -> Projects and Solutions -> .NET Core page.

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Note! (don't use it on your developer machine)

0- make sure you installed .net core 3 sdk. dotnet --list-sdks

1- make sure Tools -> Options that enables preview versions of the .NET Core SDK enabled.

2- uninstall all x86 version of .net core sdk from your machine.

3- restart visual studio and try to create a new project.

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In my case is because I did not installed Visual Studio 2019 with that feature. So just create a new project and type .net core. Then click on Install more tools and features:

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Then add the following feature:

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Tried to get .NET Core 3 (preview 8 in my case) to work in the release version of Visual Studio 2019 but ASP.NET Core 3.0 refused to show up in the "Create new ASP.NET Core web application" dialog.

What eventually worked was to install the Preview version of Visual Studio 2019.

I could have saved a few hours and a lot of hair if I had taken the warning text ".NET Core 3.0 should be used with the latest previews of Visual Studio." (https://dotnet.microsoft.com/download/dotnet-core/3.0) more literally...

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I was not able to get .netcore 3.0 preview8 working on my Visual Studio Community Edition (version 16.2.3). I opted to uninstall .netcore 3.0 preview8 and I installed .netcore 3.0 preview7 instead. After insalling .netcore 3.0 preview7 In Visual Studio I checked use previews of the .NET Core SDK option that is in Tools -> Options -> Preview Features and I restarted it. That worked for me, but if someone have .netcore 3.0 preview8 already working, help will be appreciated it.

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It no longer works... again!

The SDK 3.0.100-preview8-013656 doesn't provide the ASP.Net Core 3.0 project template.

You have to uninstall it and install SDK 3.0.100-preview7-012821

https://dotnet.microsoft.com/download/dotnet-core/3.0

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I had this problem and solved it as follows:

STEP 1: Download .NET Core 3.0

STEP2: Enable the ability to consume preview SDKs by default, As shown below:

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I've encountered the same problem on a Mac and found a solution to this issue. On visual studio update tab (Visual Studio -> check for updates) there is a option to change channel to "Preview". Switch to Preview

After that you can download necessary updates and go using .net core 3.0

now there is option to change SDK to 3.0

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Here is what I did to show .NET Core 3.0 in VS2019

  1. Installed .NET Core 3.0 SDK (No Success)
  2. Restarted VS2019 after installing .NET Core 3.0 SDK (No Success)
  3. Updated VS2019 (Worked Perfectly)
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I had the same issue. Here is what worked for me.

  • First, download the latest .Net Core 3.0 SDK (see 1,2 below).

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  • Next, Check for updates (4,5). (this is what helped me the most)

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  • Next, Enable Preview SDK (5,6,7,8,9) and restart

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  • Now, the .net core 3.0 option should show (11).
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I had the very same issue. I tried everything with no success

I already had only x64 version of .NET Core SDK

In addition i had to install x86 version too. That WORKED !!!

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If your solution uses global.json and sdk:version isn't compatible with the target framework, it won't let you select it or it disappears from Target framework drop-down in your project's properties. You will need to update it to something like this:

{
"sdk": {
"version": "3.1.0",
"rollForward": "latestMinor"
}
}
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I noticed an interesting behavior. I had the latest version of VS with all the dependencies installed. But when I try to add a new project to the solution, the dialog does not show me the options beyond .Net Core 2.2

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But When I create the new project from the startup page, the drop down does show the ASP.NET Core 3.1

So I was able to work around the issue by creating the new project from the startup page, then add the existing project to the solution.

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I've had the same issue after installing .net core 3.1. This is how I resolved it.

  1. open powershell, type dotnet --version, it returns '2.2.300'
  2. go to 'programs and features', unistall .net core sdk 2.2.3.0
  3. run dotnet --version again, it returns '3.1.302' and in VS 2019 it shows '.net 3.1'
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I resolved it by installing

dotnet-sdk-3.1.403-win-x86.exe dotnet-sdk-3.1.403-win-x64.exe Because the visual studio was taking the SDK from "C:\Program Files (x86)\dotnet\sdk" once you install "dotnet-sdk-3.1.403-win-x86.exe" there will one folder under the above directory. then no need to restart your PC.

https://dotnet.microsoft.com/download/visual-studio-sdks?utm_source=getdotnetsdk&utm_medium=referral

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This answer is for the newest .NET Core version as of 10/11/2020, which is .NET Core 5.0

Specs: VS Version 16.8.0

Target Version of .Net Core: 5.0

You must have version 16.8.0 in order to have .Net Core 5.0

If you still have problems with Visual Studio not showing .Net Core 5.0 in Visual Studio version 16.8.0 (and assuming you downloaded the .NET Core 5.0 SDK for Visual Studio), well, apparently (and correct me if I'm wrong) it is now called just .Net 5.0, omitting the Core.

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After selecting .NET 5.0, I was able to install other libraries which are currently version 5.0+ and dependent on .NET Core 5.0+

Is the new name intentional? Anyways, here some evidence of this working (I was able to install the newest version of Newtonsoft and Entity Framework for .Net Core):

enter image description here

Funny enough, when I try to create a new .Net Core project, the version shows up as expected:

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I'm very sorry for my English!

[PS: I'm literally copying&pasting this answer, which I answered somewhere else, but given that, when you Google this issue, this stackoverflow question appears first. So thats why I'm reposting]

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ASP.Net Core 3.0+ just runs on vs2019 version 16.7+. You need to go to help tab on your visual studio and check for updates and update it to the latest version


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