Microsoft .NET Framework 4已经是此操作系统的一部分。 您不需要安装.NET Framework 4可再发行组件

Question

I have VS 2010, VS 2012 on Windows 8. I tried to uninstall a trial version of VS 2015. The installer uninstalled .NET 4.0, 4.5 frameworks Our project in source control is on .Net 4.5. When I tried to install 4.0, 4.5 this is the message. What should I do?

Answer 1

Since you are using Windows 8, your .NET Framework is version 4.5 by default. This means on Windows 8, you already have .NET Framework 4.5.

The default behavior of .NET Framework on Windows is any new release of Windows is also has minimum version of .NET Framework runtime installed . Also the .NET Framework version that comes with Windows can't be downgraded.

For example: in your case, Windows 8 has .NET Framework 4.5 installed. If you have Windows 8.1, you will have .NET Framework v4.5.1 already installed. Therefore you can not install .NET Framework v4.0 (or v4) on your Windows 8.

On Visual Studio 2012 and later, there are .NET Framework targeting packs, and this will enable software/application development to target a specific version of .NET Framework, and your screenshot that has the .NET Framework version values has the supported .NET Framework target, not related to any installed .NET Framework.

Of course we have to consider the fact that your .NET Framework runtime on your current Windows must be upgraded to support higher version of .NET Framework.

For example: to run an application that was developed using .NET Framework 4.7 as the main target on Windows 8, you must ensure that .NET Framework v4.7 runtime is installed on Windows 8, because Windows 8 by default has .NET Framework 4.5.

For more information, this is the Microsoft's official documentation related version on Windows and .NET Framework runtime versions: https://docs.microsoft.com/en-us/dotnet/framework/migration-guide/versions-and-dependencies