Access Cookbook

Run the Application Associated with a Data File

Problem

You’d like to find a way to provide a list of existing files, allow users to select a file, and run the appropriate application for that file. Windows knows how to do this—for instance, when you double-click on a file with a .TXT extension in Explorer, Windows runs Notepad with that file. How can you provide this sort of functionality in your own applications?

Solution

Windows provides two API functions, FindExecutable and ShellExecute, that make running a related application possible from within Access. Both functions rely heavily on the Windows registry, which tracks the relationships between filename extensions and related executable programs. Figure 11-8 shows the results of running the REGEDIT.EXE program, which ships as part of Windows. REGEDIT allows you to add, edit, modify, or delete file associations. (The registry editor is named REGEDT32.EXE under Windows NT and, though it looks different, it functions in a similar manner.)

Figure 11-8. REGEDIT.EXE, showing file types registered on a typical system

Tracing File Associations in REGEDIT

If you want, you can follow the paths of file associations in REGEDIT.EXE. Starting from the HKEY_CLASSES_ROOT item, open the folder (by double-clicking) and look for the .txt entry. If you select that item, you’ll see that the default value (on the right side of REGEDIT’s display) ...