如何将.NET Framework 3.5 SP1安装到Visual Studio 2017中

Question

I am migrating a project from VS 2008 to VS 2017.

When I opened the project in VS2017 I was prompted if I wanted to update it to 4.6.1, or keep it as 3.5.

I chose to keep it at 3.5 and a browser window opened to this page: https://www.microsoft.com/net/download/visual-studio-sdks

Presumably that is to download 3.5. However, there is no "Developer Pack" for 3.5.

So I don't have clear idea of what to do.

Here are some additional notes: There is not solution file in this project. I opened it in VS2017 using File -> Open -> Website...

I am willing to update to 4.6.1. I am deploying to IIS 8.0.9200 if anyone has additional tips on updating to 4.6.1.

I am a long time coder, but I am new to windows development so if your answers can use terminology that I see on the screen then it will be helpful for me to understand the answers.

to move forward I choose to update to 4.6.1 because the screen explicitly stated I could move back to 3.5.

Answer 1

You should install the .NET 3.5 development tools using the Visual Studio Installer.

Instructions:

1. Close Visual Studio (the next step will close it for you, but it's better to close it yourself so you are in a known state).
2. Open the Visual Studio Installer (search for it in the Start menu).
3. Choose to modify the installation you desire.
4. Go to the "Individual Components" tab.
5. Under the ".NET" section choose ".NET Framework 3.5 Developer Tools".
6. Click "Modify" in the bottom right corner to apply the changes.

You may also need to turn on the Windows Feature .Net Framework 3.5 (includes .NET 2.0 and 3.0) .

Answer 2

I had the same issue. Go to Windows Control panel over there add features to windows. Then check .NET framework 3.5. Done! https://improveandrepeat.com/2018/07/an-alternative-way-to-install-net-3-5-on-windows-10/

(you should also check if you already haven't ".NET 3.5 development tools" using the Visual Studio Installer.)