Selecting a directory with TOpenDialog

Question

I\'d really like to know the various ways I could select a directory with the TOpenDialog, whether it be downloading a new component or using what is provided by Delphi, but

Answer 1

Just found the code below that seems to work fine in XP and Vista, Win7. It provides a UI for a user to select a directory. It uses TOpenDialog, but sends it a few messages to clean up the appearance for the purposes of selecting a directory.

After suffering from the limited capabilities provided by Windows itself, it's a pleasure to be able to give my users a familiar UI where they can browse and select a folder comfortably.

I'd been looking for something like this for a long time so thought I'd post it here so others can benefit from it.

Here's what it looks like in Win 7:

//***********************
//** Choose a directory **
//**   uses Messages   **
//***********************
  //General usage here:
  //  http://www.delphipages.com/forum/showthread.php?p=185734
  //Need a class to hold a procedure to be called by Dialog.OnShow:
  type TOpenDir = class(TObject)
  public
    Dialog: TOpenDialog;
    procedure HideControls(Sender: TObject);
  end;
  //This procedure hides de combo box of file types...
  procedure TOpenDir.HideControls(Sender: TObject);
  const
    //CDM_HIDECONTROL and CDM_SETCONTROLTEXT values from:
    //  doc.ddart.net/msdn/header/include/commdlg.h.html
    //  CMD_HIDECONTROL = CMD_FIRST + 5 = (WM_USER + 100) + 5;
    //Usage of CDM_HIDECONTROL and CDM_SETCONTROLTEXT here:
    //  msdn.microsoft.com/en-us/library/ms646853%28VS.85%29.aspx
    //  msdn.microsoft.com/en-us/library/ms646855%28VS.85%29.aspx
    CDM_HIDECONTROL =    WM_USER + 100 + 5;
    CDM_SETCONTROLTEXT = WM_USER + 100 + 4;
    //Component IDs from:
    //  msdn.microsoft.com/en-us/library/ms646960%28VS.85%29.aspx#_win32_Open_and_Save_As_Dialog_Box_Customization
    //Translation into exadecimal in dlgs.h:
    //  www.koders.com/c/fidCD2C946367FEE401460B8A91A3DB62F7D9CE3244.aspx
    //
    //File type filter...
    cmb1: integer  = $470; //Combo box with list of file type filters
    stc2: integer  = $441; //Label of the file type
    //File name const...
    cmb13: integer = $47c; //Combo box with name of the current file
    edt1: integer  = $480; //Edit with the name of the current file
    stc3: integer  = $442; //Label of the file name combo
  var H: THandle;
  begin
    H:= GetParent(Dialog.Handle);
    //Hide file types combo...
    SendMessage(H, CDM_HIDECONTROL, cmb1,  0);
    SendMessage(H, CDM_HIDECONTROL, stc2,  0);
    //Hide file name label, edit and combo...
    SendMessage(H, CDM_HIDECONTROL, cmb13, 0);
    SendMessage(H, CDM_HIDECONTROL, edt1,  0);
    SendMessage(H, CDM_HIDECONTROL, stc3,  0);
    //NOTE: How to change label text (the lentgh is not auto):
    //SendMessage(H, CDM_SETCONTROLTEXT, stc3, DWORD(pChar('Hello!')));
  end;
//Call it when you need the user to chose a folder for you...
function GimmeDir(var Dir: string): boolean;
var
  OpenDialog: TOpenDialog;
  OpenDir: TOpenDir;
begin
  //The standard dialog...
  OpenDialog:= TOpenDialog.Create(nil);
  //Objetc that holds the OnShow code to hide controls
  OpenDir:= TOpenDir.create;
  try
    //Conect both components...
    OpenDir.Dialog:= OpenDialog;
    OpenDialog.OnShow:= OpenDir.HideControls;
    //Configure it so only folders are shown (and file without extension!)...
    OpenDialog.FileName:= '*.';
    OpenDialog.Filter:=   '*.';
    OpenDialog.Title:=    'Chose a folder';
    //No need to check file existis!
    OpenDialog.Options:= OpenDialog.Options + [ofNoValidate];
    //Initial folder...
    OpenDialog.InitialDir:= Dir;
    //Ask user...
    if OpenDialog.Execute then begin
      Dir:= ExtractFilePath(OpenDialog.FileName);
      result:= true;
    end else begin
      result:= false;
    end;
  finally
    //Clean up...
    OpenDir.Free;
    OpenDialog.Free;
  end;
end;

Answer 2

You do know that the two overloaded functions called FileCtrl.SelectDirectory produces entirely different dialogs, right?

SelectDirectory(s, [], 0);

SelectDirectory('Select a directory', s, s, []);

Answer 3

If you are using JVCL you can use TJvSelectDirectory. With this you can switch between old and new style by setting a property. For example:

Dlg := TJvSelectDirectory.Create(Self);
try
    Dlg.Title := MyTitle;
    Dlg.InitialDir := MyStartDir;
    Dlg.Options := Dlg.Options + [sdAllowCreate, sdPerformCreate];     
    Dlg.ClassicDialog := False;   //switch style
    if Dlg.Execute() then
      NewDir := Dlg.Directory;
finally
    Dlg.Free;
end; 

Answer 4

Just include

FileCtrl.pas

var
  sDir:String;
begin
  SelectDirectory('Your caption','',sDir);
end;

Just leave second argument empty if want to see all directories including desktop. If you set second argument to any valid Path, then your dialog will have that path to top folder and you can not navigate beyond that.

For example:

SelectDirectory('Your caption','C:\',sDir) will not let you select anything beyond C:\, like D:\ or E:\ etc.

So it is good to leave it empty.

Answer 5

You can use the TFileOpenDialog (on Vista+):

with TFileOpenDialog.Create(nil) do
  try
    Options := [fdoPickFolders];
    if Execute then
      ShowMessage(FileName);
  finally
    Free;
  end;

Personally, I always use the TFileOpenDialog on Vista+ and fallback using the SelectDirectory (the good one!) on XP, like this:

if Win32MajorVersion >= 6 then
  with TFileOpenDialog.Create(nil) do
    try
      Title := 'Select Directory';
      Options := [fdoPickFolders, fdoPathMustExist, fdoForceFileSystem]; // YMMV
      OkButtonLabel := 'Select';
      DefaultFolder := FDir;
      FileName := FDir;
      if Execute then
        ShowMessage(FileName);
    finally
      Free;
    end
else
  if SelectDirectory('Select Directory', ExtractFileDrive(FDir), FDir,
             [sdNewUI, sdNewFolder]) then
    ShowMessage(FDir)