Whenever you're doing stuff that takes a significant amount of time in an application with GUI you want to put it in a seperate thread so the user can still operate the form. You can declare a simple thread as such:
TWorkingThread = class(TThread)
protected
procedure Execute; override;
procedure UpdateGui;
procedure TerminateNotify(Sender: TObject);
end;
procedure TWorkingThread.Execute;
begin
// do whatever you want to do
// make sure to use synchronize whenever you want to update gui:
Synchronize(UpdateGui);
end;
procedure TWorkingThread.UpdateGui;
begin
// e.g. updating the progress bar
end;
procedure TWorkingThread.TerminateNotify(Sender: TObject);
begin
// this gets executed when the work is done
// usually you want to give some kind of feedback to the user
end;
// ...
// calling the thread:
procedure TSettingsForm.Button1Click(Sender: TObject);
var WorkingThread: TWorkingThread;
begin
WorkingThread := TWorkingThread.Create(true);
WorkingThread.OnTerminate := TerminateNotify;
WorkingThread.FreeOnTerminate := true;
WorkingThread.Start;
end;
It's pretty straight forward, remember to always use Synchronize when you want to update visual elements from a thread. Usually, you also want to take care that the user can't invoke the thread again while it's still doing work as he's now able to use the GUI.