type
  TNetResourceArray = TArray<TNetResource>;

function EnumerateContainedPrinters(const AContainer: TNetResource): TNetResourceArray;
var
  LResult, LBufferSize: DWORD;
  LEnumHandle: THandle;
  LNetResources: TNetResourceArray;
  I: Integer;
  LEntries : Longint;
begin
  LEntries := -1;
  LBufferSize := 16384;
  LResult := WNetOpenEnum(RESOURCE_GLOBALNET, RESOURCETYPE_PRINT, RESOURCEUSAGE_CONNECTABLE, @AContainer, LEnumHandle);
  if LResult = NO_ERROR then
  try
    SetLength(LNetResources, LBufferSize div SizeOf(TNetResource));
    LResult := WNetEnumResource(LEnumHandle, DWORD(LEntries), @LNetResources[0], LBufferSize);
    SetLength(Result, LEntries);
    for I := 0 to LEntries - 1 do
      Result[I] := LNetResources[I];
  finally
    WNetCloseEnum(LEnumHandle);
  end;
end;

function EnumeratePrinters: TNetResourceArray;
var
  LResult, LBufferSize: DWORD;
  LEnumHandle: THandle;
  LNetResources, LPrinters: TNetResourceArray;
  I: Integer;
  LEntries : Longint;
begin
  LEntries := -1;
  LBufferSize := 16384;
  LResult := WNetOpenEnum(RESOURCE_CONTEXT, RESOURCETYPE_PRINT, 0, nil, LEnumHandle);
  if LResult = NO_ERROR then
  try
    SetLength(LNetResources, LBufferSize div SizeOf(TNetResource));
    LResult := WNetEnumResource(LEnumHandle, DWORD(LEntries), @LNetResources[0], LBufferSize);
    for I := 0 to LEntries - 1 do
    begin
      if (LNetResources[I].dwUsage = RESOURCEUSAGE_CONTAINER) and (LNetResources[I].dwType = RESOURCETYPE_PRINT) then
        Result := Concat(Result, EnumerateContainedPrinters(LNetResources[I]));
    end;
  finally
    WNetCloseEnum(LEnumHandle);
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  LPrinter: TNetResource;
begin
  for LPrinter in EnumeratePrinters do
  begin
    if LPrinter.dwType = 2 then
      ListBox1.Items.Add(Format('%s (%s)', [LPrinter.lpComment, LPrinter.lpRemoteName]));
  end;
end;