How to List Available Drives from Visual FoxPro

• Microsoft Visual FoxPro for Windows, version 3.0

SUMMARY

This article shows by example how to determine which drive letters and types are available on your computer. The sample code in this article can be used to list the available drives and their types.

MORE INFORMATION

The sample code in this article uses two API functions; DRIVETYPE() and WNetGetConnection():

• DRIVETYPE(): The syntax for DRIVETYPE is:

  x = DRIVETYPE(<expC>)

  Here <expC> is the drive letter for which you want to know the drive type. DRIVETYPE() returns a numeric value representing the drive type of the drive . Possible return values are:

  0 - Drive does not exist 1 - Drive has no root directory 2 - Floppy Disk 3 - Hard Disk 4 - Removable or Network drive 5 - CD-ROM 6 - RAM Disk

  The DRIVETYPE function is included in FOXTOOLS.FLL. For more information on this function, please see FOXTOOLS.HLP in the VFP directory.

• WNetGetConnection(): When passed a valid network drive letter, the WNetGetConnection() function returns the name of the network resource. The syntax for WNetGetConnection() is:

  x = WNetGetConnection(lpszLocalName, lpszRemoteName, lpcchBuffer)

  Here lpszLocalName points to a buffer containing the local drive letter, lpszRemoteName points to a buffer that will receive the network resource name and lpcchBuffer points to a variable that contains the size, in characters, of the buffer pointed to by lpszRemoteName. WNetGetConnection is NOT part of FOXTOOLS.FLL, consequently before using this function you must declare it. For more information on this function see WIN32API.HLP.

Code Sample

The following code sample echos to the desktop drive letters A through Z, and displays the drive type of each. To run this example, open a new program (.prg) file, enter the following code, and run it:

** BEGIN CODE SAMPLE SET LIBRARY TO \VFP\FOXTOOLS.FLL & Register the FOXTOOLS Library DECLARE INTEGER WNetGetConnection IN win32api ;

     STRING lpszLocalName,;
     STRING lpszRemoteName,;
     INTEGER @ lpchBuffer && Declare the external WNetGetConnection ;
     API function

     DRIVE = CHR(I + 64)
     DTYPE = DRIVETYPE(drive) && Determine drive type
     DO CASE
          CASE DTYPE = 0 && Non existent drives
              ? "Drive " + DRIVE + ": does not exist"
          CASE DTYPE = 1 && No root directory
              ? "Drive " + DRIVE + ": has no root directory"
          CASE DTYPE = 2 && Floppy drives
               ? "Drive " + DRIVE + ": is a floppy drive"
          CASE DTYPE = 3 && Hard drives
               ? "Drive " + DRIVE + ": is a local hard drive"
          CASE dtype = 4 && Removable or network drives
               iSuccess = WNetGetConnection(drive + ;
               ":",@slpRemoteName,@slen)
               IF iSuccess = 0
                    ? "Drive " + Drive + ": is a network" + ;
                    " drive connected to " + LEFT(slpRemoteName,;
                    ATC(chr(0),slpRemoteName) - 1)
               ENDIF
          CASE DTYPE = 5 && CD-ROM drives
               ? "Drive " + DRIVE + ": is a CD ROM drive"
          CASE DTYPE = 6 && RAM drives
               ? "Drive " + DRIVE + ": is a RAM drive"
     ENDCASE