your own dialog form

your own Dialog Form

Introduction
Dialog forms are forms, that pop-up at runtime to request information from
the user. After this information is supplied the user clicks an OK or a CANCEL
button to resume operation.

Delphi has ready-to-use dialogs for openening- and saving files, selecting fonts etc.

Until recently I constructed my own dialog forms using statements as
mydialogForm.show and suspending operation by
application.processmessages or supplying a procedure to be called after
closing of the dialogForm.
Code was added to disable/enable the calling form.
There is an easier way.

the Recipe
Add button1 with caption 'dialog' to form1.
Add label1 to this form.

The code of unit1:

unit Unit1;
interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Label1: TLabel;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

uses Unit2;

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
 if form2.execute then label1.caption := 'OK'
  else label1.caption := 'cancel';
end;

end.

Add Form2 (the dialog form).
Add button1 with caption 'OK' and set modalresult to mrOK in the object inspector.
Add button2 with caption 'CANCEL' and set modalresult to mrCancel.

Add a function execute to TForm2.

The code for unit2:

unit Unit2;
interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm2 = class(TForm)
    Button1: TButton;
    Button2: TButton;
  private
    { Private declarations }
  public
   function execute : boolean;
  end;

var
  Form2: TForm2;

implementation

{$R *.DFM}

function TForm2.execute : boolean;
begin
 showmodal;
 if modalResult = mrOK then result := true else result := false;
end;

end.

That's all.
Processing is suspended after the showModal statement in unit2,
form2 pops up and form1 is disabled.
Pressing button1 or button2 sets the modalresult of form2 <> 0, processing
resumes, form2 closes and form1 is enabled.
Any processing needed on form2 may be started by the onShow event.

OneStat