The VS2010 version no longer has a separate MSDN Library installation package, the VS2010 ISO installation CD already contains the MSDN Library, and the manual installation steps are as follows:
1. Start the Visual Studio 2010 application, and select Help, manage Help settings, and pop up the assist Library manager.
2. Click on "Choose Online Help or local Help" in the Library manager to bring up the "Settings" screen and select "I want to use local Help" in this screen.
3. Click "Install content from disk" in the Help Library manager, pop up the "Install content from disk" screen, then select the productdocumentation\ under the VS2010 installation CD Helpcontentsetup.msha file, and then click Next.
4. In the "Install content from disk" interface, "add" need help file, it is best to click "Update" to start the installation, and finally complete the installation of your local Help library.
Visuall Studio Help Installation method