When you might need the CAB separately

microsoft-windows-netfx3-ondemand-package.cab 并非什么神秘的代码，而是微软提供的一个功能强大的离线组件包载体。通过理解其与操作系统的版本绑定关系，并掌握 DISM 这一核心工具的使用方法，您就可以轻松应对 .NET Framework 3.5 安装难题。

While many guides suggest downloading the full Windows 10/11 ISO to access the \sources\sxs folder, obtaining this specific .cab file is a leaner approach. You only need a single file, just a few dozen megabytes in size, without the hassle of downloading a multi-gigabyte ISO image.

Wait for the progress bar to reach 100%. You will see a message stating, "The operation completed successfully." Method 2: Windows PowerShell

If you want, I can provide:

Once the DISM utility finishes processing and displays "The operation completed successfully," you can confirm the installation is active. Open the Run dialog box by pressing . Type optionalfeatures and press Enter .

Type or copy-paste the following command into the prompt, then hit :

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Instead, use these authorized, safe methods to acquire the genuine package:

Right-click the install_netfx3.bat file and select .

Download the official Windows Media Creation Tool or a Windows ISO directly from Microsoft.

DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /Source:D:\sources\sxs /LimitAccess Use code with caution.

简单来说，这是一个 Windows 操作系统组件包。 .cab 是 Cabinet（文件柜）的缩写，是微软用于分发系统软件、驱动程序和重要更新的一种压缩存档格式。 microsoft-windows-netfx3-ondemand-package.cab 专门包含了在 Windows 10 和 Windows 11 上安装 .NET Framework 3.5（包括 .NET 2.0 和 3.0）所需的所有源文件。

Type , right-click Command Prompt , and select Run as administrator .

在一些技术社区或代码托管平台（如 GitHub），有热心开发者会分享官方的 CAB 文件镜像，但请务必注意源文件的真实性和与系统的匹配度。

In the Windows Features window, look at the very top of the list.