The compiler checks your code against the exact API surface area of .NET 4.0. If you accidentally use a class or method introduced in .NET 4.5 or later, the IDE throws a compile-time error rather than failing at runtime on the client's machine.
While newer versions of Visual Studio (2022+) have deprecated built-in support for .NET 4.0 - 4.5.1, you can still integrate these packs manually. Microsoft Learn Multi-Targeting Pack for the Microsoft .NET Framework 4.0.3
无论是已经在这条路上摸爬滚打多年的资深开发者，还是刚刚踏入这片领域的新手，或许都曾在一个看似矛盾的问题上感到困惑：为什么我已经在电脑上安装了 .NET Framework 4，Visual Studio 却依然报错说找不到相关组件？又或者，当你在“控制面板”的“添加/删除程序”列表中随意浏览时，会看到一个名为“Microsoft .NET Framework 4 Multi-Targeting Pack”的条目。这究竟是什么？它与我们已经非常熟悉的 .NET Framework Runtime（运行时）到底有什么不同？
Search for (or the specific version required). Check the box, click Modify , and restart Visual Studio. microsoft .net framework 4 multi targeting pack
Select ".NET Framework 4" from the list. If you do not see it, you may need to install the targeting pack.
: .NET Framework 4.0, 4.5, and 4.5.1 have reached their end of life and are no longer supported by Microsoft.
Install only if a modern targeting pack fails to build your .NET 4.0 project. Otherwise, skip it and use the latest Developer Pack for .NET Framework 4.8. The compiler checks your code against the exact
If you are using Visual Studio 2022 but need to maintain a legacy tool that must run on machines only supporting .NET 4.0, you cannot use modern API features. The targeting pack limits IntelliSense and compilation to the 4.0 subset, preventing "method not found" errors at runtime.
It ensures that the application created is compatible with the .NET Framework 4.0 CLR (Common Language Runtime). Key Components of the Targeting Pack
This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. Microsoft Learn Multi-Targeting Pack for the Microsoft
: Each pack targets a specific update. For instance, the pack for .NET Framework 4.0.3 is cumulative, meaning it allows building projects for 4.0.1, 4.0.2, and 4.0.3. Microsoft Support Why Developers Use It The primary benefit is flexibility
The .NET Framework 4 family saw a series of updates that introduced both runtime improvements and new APIs. To support these changes, Microsoft released corresponding multi-targeting packs that allowed developers to build applications that leverage these new features.