How To Add & Remove Network Connections in Visual FoxPro

• Microsoft Visual FoxPro for Windows, versions 3.0, 5.0

SUMMARY

Using the Windows API (Application Programming Interface) in conjunction with Foxtools.fll in FoxPro for Windows 2.x or DECLARE DLL in Visual FoxPro, you can add and remove network connections from within FoxPro.

Although Visual FoxPro still supports the FOXTOOLS library for backward compatibility, the DECLARE command is the preferred method for calling DLL functions.

MORE INFORMATION

The following sections cover the FoxPro 2.x and Visual FoxPro usage conventions.

FoxPro 2.x

In FoxPro 2.x using the FOXTOOLS library, you need to use the following steps to add and remove network connections.

1. Use the following command to establish the library:

   SET LIBRARY TO SYS(2004)+'FOXTOOLS.FLL' ADDITIVE

2. Register the Windows API functions that you need to call. In this case, WNetAddConnection() and WNetCancelConnection().

   addconn=RegFn('WNetAddConnection','CCC','I') delconn=RegFn('WNetCancelConnection','CI','I')

3. To connect to a network device, issue the following command:

   =CallFn(addconn,"\\SERVER\SHARE","password","<drive>:")

4. To disconnect from a network connection, issue the following command:

   =CallFn(delconn,"<drive>:",0)

Visual FoxPro

Using the DECLARE DLL functionality, the previous steps can be reduced to the following commands:

**-- Set up API calls Declare integer WNetAddConnection in WIN32API string,string,string Declare integer WNetCancelConnection in WIN32API String,integer

**-- Add a network connection =WNetAddConnection("\\SERVER\SHARE", "", "DriveLetter:")

**-- Remove a network connection =WNetCancelConnection("DriveLetter:",0)

The following information provides additional reference material on the two API calls used.

WNetAddConnection()

The WNetAddConnection() function redirects the specified local device (either a disk drive or a printer port) to the given shared device or remote server. It takes the following parameters:

   lpszNetPathName   A pointer to a null-terminated string specifying
                     the shared device or remote server, such as
                     \\Server\Share.

                     NOTE: Novell users should not use the double-colon
                     syntax to reference a server and directory as they may
                     be accustomed to doing. For example, do not try
                     referencing a directory using this syntax:
                     \\server\volume::\mydirectory. Instead, use this
                     syntax: \\server\volume\mydirectory

   lpszPassword      A pointer to a null-terminated string specifying
                     the network password for the given device or
                     server. If there is no password, you must still
                     include a placeholder, as follows:

                     =CallFn(addconn,"\\SERVER\SHARE","","<drive>:")

   lpszLocalName     A pointer to a null-terminated string specifying
                     the local drive or device to be redirected. All
                     lpszLocalName strings (such as LPT1) are
                     case-independent. Only the drive names A through
                     Z and the device names LPT1 through LPT3 are
                     used.

WNetCancelConnection()

The WNetCancelConnection() function cancels a network connection. It takes the following parameters:

   lpszName          A pointer to the name of the redirected local
                     device (such as LPT1: or D:).

   fForce            A Boolean value that specifies whether any open
                     files or open print jobs on the device should be
                     closed before the connection is canceled.

REFERENCES

For more information about the WNetAddConnection() and WNetCancelConnection() API calls, please see the Microsoft Windows Software Development Kit (SDK) "Programmer's Reference, Volume 2: Functions," which contains information about the functions' return values and their meanings.

NOTE: The API call return values will not be interpreted by FoxPro for Windows.

For information about the Visual FoxPro DECLARE method, please see the "DECLARE - DLL" Help topic.