Visual Studio 2019 似乎没有看到我安装了 .NET Core 3.1（使用 SDK）

Question

I just installed Visual Studio a few days ago and for some reason I can't create anything but a class.

When I go to create a new User Control the pop up window lets me do everything except for click the "Add" Button to close the window and create the control.

If I double-click the User Control selector to create automatically, it pops up an alert box that says I need to go to the installer to get the .NET Framework target libraries. But when I go to the project's properties I see that I am already targeting .NET Core 3.1 and the only other option I have to target is .NET Core 3.0.... I assume this is because I'm in a .NET Core WPF application but I have no idea why it won't let me create a new control. It won't let me create anything except for a new class.

What is going on here? How can I work around this bug?

Answer 1

I'v faced your problem recently. most of templates were not installed after installation.

something you have to do is Modifying your installation.

open Visual Studio Installer and click on Modify then choose the features (.Net core,Asp.net,Desktop Application and etc) in order to re-install them.

keep it in mind that, if installer encounters any problem or missing dll . installation instantly will be completed that should not happen. keep your eyes close to your installer process and make sure all packages are installed.

a successful installation MUST not have any warning otherwise there are packages not installed.

it's better to install packages one by one NOT totally.i mean if you want Asp.Net Core feature then try to install it at first. then try to install another feature. Actually i was not able to install whole features at single installation and i don't know why. in short , don't heavy your installation .

If the problem still exists then:

1. Close all open solutions

2. Run InstallCleanup.exe

C:\\Program Files (x86)\\Microsoft Visual Studio\\Installer\\resources\\app\\layout\\InstallCleanup.exe

3. Remove all existing Visual Studio programs from Control Panel -> program features

4. Restart pc and re-install Visual Studio

5. Make sure you have connected to network

6. Choose only one feature(Don't select all) to install + Visual Studio Editor

vs bug

Extensions don't work properly in VS 2019 and make it hang.it's may happen because of the Extensions have to be updated to be compatible to vs 2019 or it's vs bug.