If you are using Visual Studio with Qt, you can ensure a more productive experience by adding the Qt directories to your Visual Studio list of includes.
In Visual Studio, add the following directories to the Win32 Platform Include files list (Tools|Options|Projects and Solution|VC++ Directories):
Make sure that the QTDIR environment variable has been defined (or else manually substitute the Qt directory for $(QTDIR) in the list items).
In the VA X Options dialog, Platform should be set to Win32 (VAssistX|Visual Assist X Options|Projects|C/C++ Directories).
VA X will parse included Qt header files the next time you open a solution that uses Qt. If you have the Stable symbols in italic option enabled, Qt symbols will be displayed in italics.
For visual sutdio 2010 sp1, the Tools|Options|Projects and Solution|VC++ Directories) setting has been deprecated. How to fix with this ?
Property sheets are used in VS2010 instead of the IDE Options dialog for setting ‘system’ include directories. Use the Property Manager to edit property sheets: View | Other Windows | Property Manager. Edit the Microsoft.Cpp.Win32.user property sheet (or create a new property sheet just for Qt projects). Once you open the Properties dialog of the property sheet, you can find VC++ Directories under Common Properties.