The following sample code sets the directory of DirectoryListBox1 to C:\WINDOWS when the form is created. When Button1 is pressed, a subdirectory called mytemp is added to C:\WINDOWS, but note that it is not updated in DirectoryListBox1 until Button2 is pressed and Update is called. Note: An EInOutError will occur if you add a directory that already exists. Also, you must add the new directory to your current path to get things started.
procedure TForm1.Button1Click(Sender: TObject); begin MkDir(Edit1.Text); end; procedure TForm1.Button2Click(Sender: TObject); begin DirectoryListBox1.Update; end; procedure TForm1.FormCreate(Sender: TObject); begin DirectoryListBox1.Directory := 'c:\WINDOWS'; end;