A InfoTip extension is one of the simplest extensions. It will display a custom infotip (sometimes called tooltip) when the user hovers the mouse above the file for which the InfoTip is registered. Some versions of explorer.exe also use the infotip string to
display it in the statusbar.
The vvv sample and the 'start' sample both a show a basic implementation of an InfoTip. The easiest approach is to copy the 'start' template and modify it.
Build the extension step by step
The basic steps to create a InfoTip extension are:
- Create an ATL DLL
- Create a ATL C++ class that will act as COM object
- Derive the COM class also from MSF::IInfoTipImpl<T>, T is your just created class.
- Add the required COM interfaces to the ATL COM_MAP:
- IPersistFile (used up to Windows XP)
- IInitializeWithFile (used by Vista and up)
- Add the ATL registrar registration script to the DLL resource section.
- Implement the method UpdateRegistry. This function is called by the ATL framework when regsvr32 us used on the DLL. MSF provides a set of helper functions to implement this method.
- Add your own code to create the string that should be returned and displayed in the infotip.