function ConnectDrive(_drvLetter: string; _netPath: string; _showError: Boolean; 
 _reconnect: Boolean): DWORD; 
var 
 nRes: TNetResource; 
 errCode: DWORD; 
 dwFlags: DWORD; 
begin 
 { Fill NetRessource with #0 to provide uninitialized values } 
 { NetRessource mit #0 fullen => Keine unitialisierte Werte } 
 FillChar(NRes, SizeOf(NRes), #0); 
 nRes.dwType := RESOURCETYPE_DISK; 
 { Set Driveletter and Networkpath } 
 { Laufwerkbuchstabe und Netzwerkpfad setzen } 
 nRes.lpLocalName := PChar(_drvLetter); 
 nRes.lpRemoteName := PChar(_netPath); { Example: \\Test\C } 
 { Check if it should be saved for use after restart and set flags } 
 { Uberprufung, ob gespeichert werden soll } 
 if _reconnect then 
 dwFlags := CONNECT_UPDATE_PROFILE and CONNECT_INTERACTIVE 
 else 
 dwFlags := CONNECT_INTERACTIVE; 

 errCode := WNetAddConnection3(Form1.Handle, nRes, nil, nil, dwFlags); 
 { Show Errormessage, if flag is set } 
 { Fehlernachricht aneigen } 
 if (errCode <> NO_ERROR) and (_showError) then 
 begin 
 Application.MessageBox(PChar('An error occured while connecting:' + #13#10 + 
 SysErrorMessage(GetLastError)), 
 'Error while connecting!', 
 MB_OK); 
 end; 
 Result := errCode; { NO_ERROR } 
end; 

function ConnectPrinterDevice(_lptPort: string; _netPath: string; _showError: Boolean; 
 _reconnect: Boolean): DWORD; 
var 
 nRes: TNetResource; 
 errCode: DWORD; 
 dwFlags: DWORD; 
begin 
 { Fill NetRessource with #0 to provide uninitialized values } 
 { NetRessource mit #0 fullen => Keine unitialisierte Werte } 
 FillChar(NRes, SizeOf(NRes), #0); 
 nRes.dwType := RESOURCETYPE_PRINT; 
 { Set Printername and Networkpath } 
 { Druckername und Netzwerkpfad setzen } 
 nRes.lpLocalName := PChar(_lptPort); 
 nRes.lpRemoteName := PChar(_netPath); { Example: \\Test\Printer1 } 
 { Check if it should be saved for use after restart and set flags } 
 { Uberprufung, ob gespeichert werden soll } 
 if _reconnect then 
 dwFlags := CONNECT_UPDATE_PROFILE and CONNECT_INTERACTIVE 
 else 
 dwFlags := CONNECT_INTERACTIVE; 

 errCode := WNetAddConnection3(Form1.Handle, nRes, nil, nil, dwFlags); 
 { Show Errormessage, if flag is set } 
 { Fehlernachricht aneigen } 
 if (errCode <> NO_ERROR) and (_showError) then 
 begin 
 Application.MessageBox(PChar('An error occured while connecting:' + #13#10 + 
 SysErrorMessage(GetLastError)), 
 'Error while connecting!', 
 MB_OK); 
 end; 
 Result := errCode; { NO_ERROR } 
end; 

function DisconnectNetDrive(_locDrive: string; _showError: Boolean; _force: Boolean; 
 _save: Boolean): DWORD; 
var 
 dwFlags: DWORD; 
 errCode: DWORD; 
begin 
 { Set dwFlags, if necessary } 
 { Setze dwFlags auf gewunschten Wert } 
 if _save then 
 dwFlags := CONNECT_UPDATE_PROFILE 
 else 
 dwFlags := 0; 
 { Cancel the connection see also at http://www.swissdelphicenter.ch/en/showcode.php?id=391 } 
 { Siehe auch oben genannten Link (Netzlaufwerke anzeigen) } 
 errCode := WNetCancelConnection2(PChar(_locDrive), dwFlags, _force); 
 { Show Errormessage, if flag is set } 
 { Fehlernachricht anzeigen } 
 if (errCode <> NO_ERROR) and (_showError) then 
 begin 
 Application.MessageBox(PChar('An error occured while disconnecting:' + #13#10 + 
 SysErrorMessage(GetLastError)), 
 'Error while disconnecting', 
 MB_OK); 
 end; 
 Result := errCode; { NO_ERROR } 
end; 


{Beispiel / Example:} 

procedure TForm1.Button1Click(Sender: TObject); 
begin 
 ConnectDrive('h:', '\\Servername\C', True, True); 
end; 

procedure TForm1.Button2Click(Sender: TObject); 
begin 
 DisconnectNetDrive('h:', True, True, True); 
end;