OnClose、OnCloseQuery、OnDestroyの違い (ID:28964)

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本文

メインフォームの場合 Close するとそのまま終了(解放)するので
OnClose と OnDestroy の違いがあまり分からないかもしれませんが

以下のようなプログラムで確認してみると理解できるかもしれません。

//---------------------------------------------------------------

unit Unit4;

interface

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

type
  TForm4 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Memo1: TMemo;
    Button5: TButton;
    Button6: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button6Click(Sender: TObject);
  private
    { Private 宣言 }
  public
    { Public 宣言 }
  end;

var
  Form4: TForm4;

implementation

uses Unit5;

{$R *.dfm}

procedure TForm4.Button1Click(Sender: TObject);
begin
    Form5 := TForm5.Create(Self);
end;

procedure TForm4.Button2Click(Sender: TObject);
begin
    Form5.Show;
end;

procedure TForm4.Button3Click(Sender: TObject);
begin
    Form5.Close;
end;

procedure TForm4.Button4Click(Sender: TObject);
begin
    Form5.Free;
end;

procedure TForm4.Button5Click(Sender: TObject);
begin
    Form5.Hide;
end;

procedure TForm4.Button6Click(Sender: TObject);
begin
    Form5.Release;
end;

end.

//----------------------------------------------------------------

unit Unit5;

interface

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

type
  TForm5 = class(TForm)
    Button1: TButton;
    RadioButton1: TRadioButton;
    procedure FormCreate(Sender: TObject);
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure FormDestroy(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure Button1Click(Sender: TObject);
  private
    { Private 宣言 }
  public
    { Public 宣言 }
  end;

var
  Form5: TForm5;

implementation

uses Unit4;

{$R *.dfm}

procedure TForm5.Button1Click(Sender: TObject);
begin

end;

procedure TForm5.FormClose(Sender: TObject; var Action: TCloseAction);
begin
    Form4.Memo1.Lines.Add('Close');
end;

procedure TForm5.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
    Form4.Memo1.Lines.Add ('CloseQuery');
end;

procedure TForm5.FormCreate(Sender: TObject);
begin
    Form4.Memo1.Lines.Add ('Create');
end;

procedure TForm5.FormDestroy(Sender: TObject);
begin
    Form4.Memo1.Lines.Add ('Destroy');
end;

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