Delphi tutorial: Select (browse for) / Create a folder

The Delphi function SelectDirectory brings up a dialog box where the user can select or enter a folder name ("directory"). You have the choice between two syntaxes:

1. SelectDirectory( Title, RootDir, DirSelected ) displays the standard Windows "Browse for Folder" dialog with a directory tree. The parameters are:

Title: the title that should appear above the directory tree.
RootDir: the directory to be used as the root of the directory tree that is shown.
DirSelected: receives the directory that was selected by the user.

2. SelectDirectory( Dir, Options, HelpCtx ) shows an additional edit-box above the directory tree. The parameters:

Dir: the starting directory.
If the user selected a folder, this is found in this same variable after the function returns.
Options: a set of values. If this is empty, no additional edit- box is showed and the user can only select an already existing folder. Options may also contain a combination of the following values:
- sdAllowCreate: an edit box appears, where the user can enter a folder name. Attention: a non-existing folder is only created if Options also contains sdPerformCreate!
- sdPerformCreate: if the folder does not exist, SelectDirectory creates it.
- sdPrompt: displays a message box that informs the user when the folder does not exist and asks if it should be created. If the user chooses OK, the folder is created.
HelpCtx: the help context ID number. Only applicable if your application uses a help-system.

In both cases, the function returns TRUE if a folder was selected, otherwise FALSE.

How to use this Delphi function? Two examples, corresponding to the pictures above:

// Syntax 1
procedure TForm1.Button1Click(Sender: TObject);
var
  DirSelected: string;
begin
  if SelectDirectory('Select a folder:', 'D:\Delphi', DirSelected)
then
    ShowMessage('You selected ' + DirSelected)
  else
    ShowMessage('You did not select a folder');
end;

// Syntax 2
procedure TForm1.Button2Click(Sender: TObject);
var
  Dir: string;
begin
  Dir := 'D:\Delphi';
  if SelectDirectory(Dir, [sdAllowCreate, sdPerformCreate, sdPrompt],
0) then
    ShowMessage('You selected ' + Dir)
  else
    ShowMessage('You did not select a folder');
end;

IMPORTANT: SelectDirectory only works if you add FileCtrl to the uses-directive near the top of your unit. For example, if it is:
uses Windows, Messages, ..., StdCtrls;
change it to:
uses Windows, Messages, ..., StdCtrls, FileCtrl;

You can download SELECTFOLDER.ZIP, the fully commented source code files for this project.

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Select or Create a folder