uses ShlObj, ActiveX;

function SelectDirCB(Wnd: HWND; uMsg: UINT; lParam, lpData: LPARAM): Integer stdcall;
begin
if (uMsg = BFFM_INITIALIZED) and (lpData <> 0) then
SendMessage(Wnd, BFFM_SETSELECTION, Integer(True), lpdata);
result := 0;
end;

function SelectDirectory(const Caption: string; const Root: WideString;
var Directory: string; Owner: THandle): Boolean;
var
WindowList: Pointer;
BrowseInfo: TBrowseInfo;
Buffer: PChar;
RootItemIDList, ItemIDList: PItemIDList;
ShellMalloc: IMalloc;
IDesktopFolder: IShellFolder;
Eaten, Flags: LongWord;
begin
Result := False;
if not DirectoryExists(Directory) then
Directory := '';
FillChar(BrowseInfo, SizeOf(BrowseInfo), 0);
if (ShGetMalloc(ShellMalloc) = S_OK) and (ShellMalloc <> nil) then
begin
Buffer := ShellMalloc.Alloc(MAX_PATH);
try
RootItemIDList := nil;
if Root <> '' then
begin
SHGetDesktopFolder(IDesktopFolder);
IDesktopFolder.ParseDisplayName(Application.Handle, nil,
POleStr(Root), Eaten, RootItemIDList, Flags);
end;
with BrowseInfo do
begin
hwndOwner := Owner; //Application.Handle;
pidlRoot := RootItemIDList;
pszDisplayName := Buffer;
lpszTitle := PChar(Caption);
ulFlags := BIF_RETURNONLYFSDIRS;
if Directory <> '' then
begin
lpfn := SelectDirCB;
lParam := Integer(PChar(Directory));
end;
end;
WindowList := DisableTaskWindows(0);
try
ItemIDList := ShBrowseForFolder(BrowseInfo);
finally
EnableTaskWindows(WindowList);
end;
Result := ItemIDList <> nil;
if Result then
begin
ShGetPathFromIDList(ItemIDList, Buffer);
ShellMalloc.Free(ItemIDList);
Directory := Buffer;
end;
finally
ShellMalloc.Free(Buffer);
end;
end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
NewDir: string;
begin
NewDir := Edit1.Text;
if SelectDirectory('Select a Directory', '', NewDir, Handle) then
Edit1.Text := NewDir;
end;