Enumerating Network Connections

How to detecting current network connections?

Answer:

From the MS-DOS prompt, you can enumerate the network connections (drives) by using the following command:

net use

Programmatically, you would call WNetOpenEnum() to start the enumeration of connected resources and WNetEnumResources() to continue the enumeration.

The following sample code enumerates the network connections:

Sample Code
procedure TForm1.Button1Click(Sender: TObject);
var
i, dwResult: DWORD;
hEnum: THANDLE;
lpnrDrv,
lpnrDrvLoc: PNETRESOURCE;
s: string;
const
cbBuffer: DWORD = 16384;
cEntries: DWORD = $FFFFFFFF;
begin
dwResult := WNetOpenEnum(RESOURCE_CONNECTED,
RESOURCETYPE_ANY,
0,
nil,
hEnum);
if (dwResult <> NO_ERROR) then
begin
ShowMessage('Cannot enumerate network drives.');
Exit;
end;
s := '';
repeat
lpnrDrv := PNETRESOURCE(GlobalAlloc(GPTR, cbBuffer));
dwResult := WNetEnumResource(hEnum, cEntries, lpnrDrv, cbBuffer);
if (dwResult = NO_ERROR) then
begin
s := 'Network drives:'#13#10;
lpnrDrvLoc := lpnrDrv;
for i := 0 to cEntries - 1 do
begin
if lpnrDrvLoc^.lpLocalName <> nil then
s := s + lpnrDrvLoc^.lpLocalName + #9 + lpnrDrvLoc^.lpRemoteName + #13#10;
Inc(lpnrDrvLoc);
end;
end
else if dwResult <> ERROR_NO_MORE_ITEMS then
begin
s := s + 'Cannot complete network drive enumeration';
GlobalFree(HGLOBAL(lpnrDrv));
break;
end;
GlobalFree(HGLOBAL(lpnrDrv));
until (dwResult = ERROR_NO_MORE_ITEMS);
WNetCloseEnum(hEnum);
if s = '' then
s := 'No network connections.';
ShowMessage(s);
end;


Author: Igor Siticov
Product: Delphi 3.x (or higher)