Code Sample to Find Application Path Using File Extension

• Microsoft Visual FoxPro for Windows, version 3.0
• Microsoft FoxPro for Windows, versions 2.5x, 2.6, 2.6a

SUMMARY

If you know the file extension of a file type that an application uses, you can quickly determine the full path of that application by reading the [EXTENSIONS] section of the WIN.INI file (the Windows 3.x initialization file). To do this programmatically from FoxPro, you can use the FOXTOOLS.FLL library to make a call to the Windows API GetPrivateProfileString() function, as the code example below demonstrates.

NOTE: For backward compatibility, Visual FoxPro still supports FOXTOOLS.FLL (included in earlier FoxPro versions), the Visual FoxPro API library that allows calls to 16-bit .DLL functions. However, in Visual FoxPro, the DECLARE command is the preferred method for calling .DLL functions.

MORE INFORMATION

NOTE: This example only works with Windows version 3.x (16-bit versions), which use the WIN.INI file. Windows NT and Windows 95 use the Registry instead of WIN.INI.

When you run this code, you will be prompted to enter the extension. For example, enter a file extension such as "XLS" (without the quotation marks) and press ENTER. If Microsoft Excel is installed, the full path to Microsoft Excel will be returned.

   SET LIBRARY TO SYS(2004)+"foxtools"
   @ 1,1 GET ext DEFAULT "     " SAY "Enter the extension: "
   READ
   ext=ALLTRIM(ext)
   IF LEN(ext)=0
      RETURN
   ENDIF
   mpath=REPLICATE(CHR(0),256)

   * Register and call the Windows API function.

   mregister=regfn("GetPrivateProfileString","CCC@CIC","I")
   mcall=callfn(mregister,"Extensions",ext,"",@mpath,256,"WIN.INI")

   mpath=ALLTRIM(mpath)
   CNT=OCCURS('\',mpath)  && find the last backslash in the path
   IF CNT=0
      ? CHR(7)
      WAIT WINDOW "File Extension Not Found"  && in the WIN.INI file
      RETURN
   ENDIF
   x=AT('\',mpath,CNT)  && find the position of the last backslash
   mpath=SUBSTR(mpath,1,x-1)  && extract just the path
   @ 2,1 SAY "The path to the executable is " + mpath