How to create a form programmatically with a couple components on it in Delphi

Question

I'm working with Delphi 7 and I'm trying to create a form programmatically. Here's my form class stub:

unit clsTStudentInfoForm;

interface

    uses Forms;

    type
        TStudentInfoForm = class (TForm)

        end;

implementation


end.

I also have a button on my main form (that's just a regular form that's supposed to create and show the form above at run-time) and when clicked it creates and shows the student form as a modal window. It does show the form but there's nothing on it. The only thing you can do is click the close button at the upper-right corner of the window to close it.

procedure TLibraryForm.btnShowStudentIfoFormClick(Sender: TObject);
var
    f : TStudentInfoForm;
begin
    f := TStudentInfoForm.CreateNew(Self);
    f.ShowModal;
    f.Free;
    f := nil;
end;

I have no idea how to add components to a programmatically-created form (not at run-time, but to the source code). Can you help me write some code that adds an Okay button to the student form as well as sets the caption and the form's height and width (the code has to be written in the student form file)?

Any suggestions and examples will be highly appreciated. Thank you.

Answer 1

Creating modal forms with controls on the fly is easy:

procedure CreateGreetingForm;
var
  frm: TForm;
  lbl: TLabel;
  edt: TEdit;
  btn: TButton;
begin

  frm := TForm.Create(nil);
  try
    lbl := TLabel.Create(frm);
    edt := TEdit.Create(frm);
    btn := TButton.Create(frm);
    frm.BorderStyle := bsDialog;
    frm.Caption := 'Welcome';
    frm.Width := 300;
    frm.Position := poScreenCenter;

    lbl.Parent := frm;
    lbl.Top := 8;
    lbl.Left := 8;
    lbl.Caption := 'Please enter your name:';

    edt.Parent := frm;
    edt.Top := lbl.Top + lbl.Height + 8;
    edt.Left := 8;
    edt.Width := 200;

    btn.Parent := frm;
    btn.Caption := 'OK';
    btn.Default := true;
    btn.ModalResult := mrOk;
    btn.Top := edt.Top + edt.Height + 8;
    btn.Left := edt.Left + edt.Width - btn.Width;

    frm.ClientHeight := btn.Top + btn.Height + 8;
    frm.ClientWidth := edt.Left + edt.Width + 8;

    if frm.ShowModal = mrOk then
      ShowMessageFmt('Welcome, %s', [edt.Text]);

  finally
    frm.Free;
  end;

end;