Delphi模拟最小化恢复关闭按钮

unit ufrmMain;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ActnList, AppEvnts, ImgList, StdCtrls, Buttons, StdActns, Menus,
ToolWin, ComCtrls;

type

//最大最小化按纽类
TMDIButton = class(TBitbtn)
private
public
//由于由Tbitn继承而来,因此需要屏蔽其获得焦点的消息
procedure wndproc(var message: Tmessage); override;
end;

TWindowMinimize = class(TWindowAction)
public
//按纽功能,将当前最前的子window状态改为wsMinimize;
procedure ExecuteTarget(Target: TObject); override;
end;

TWindowRestore = class(TWindowAction)
public
//按纽功能,将当前最前的子window状态改为wsNormal;
procedure ExecuteTarget(Target: TObject); override;
end;

TFrmMain = class(TForm)
//保存windows的最小化,恢复,关闭的图标
MDIImageList: TImageList;
//当程序不忙时,判断最大,最小化按纽的是否应该隐藏还是可见
ApplicationEvents1: TApplicationEvents;
//
ActMdiForm: TActionList;
ToolBar1: TToolBar;
MainMenu1: TMainMenu;
N1: TMenuItem;
open1: TMenuItem;
help1: TMenuItem;
procedure FormCreate(Sender: TObject);
procedure ApplicationEvents1Idle(Sender: TObject; var Done: Boolean);
procedure FormResize(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure open1Click(Sender: TObject);
private
//模拟mdiform窗体最小化,关闭及恢复按纽对象
BtnMin, BtnRestore, BtnClose: TMDIButton;
Windowclose: TWindowClose;
WindowMinimize: TWindowMinimize;
WindowRestore: TWindowRestore;
procedure SetMDIFormActionPos;
public
{ Public declarations }
end;

var
FrmMain: TFrmMain;

implementation

{$R *.dfm}

procedure TFrmMain.FormCreate(Sender: TObject);
begin
//建立关闭Button
BtnClose := TMDIButton.Create(self);
BtnClose.Visible := false;
BtnClose.Parent := self;
BtnClose.Width := 16;
Btnclose.Height := 15;
//建立关闭功能Action
WindowClose := TWindowClose.Create(nil);
//指定其图标
WindowClose.ActionList := ActMdiForm;
WindowClose.ImageIndex := 2; //关闭;
WindowClose.Caption := '';
//将action与button关联
BtnClose.Action := WindowClose;
BtnClose.BringToFront;
BtnClose.Visible := false;

//建立最小化Button
BtnMin := TMDIButton.Create(self);
BtnMin.Visible := false;
BtnMin.Parent := self;
BtnMin.width := 16;
BtnMin.height := 15;
//建立最小化功能action
WindowMinimize := TWindowMinimize.Create(nil);
//指定其图标
WindowMinimize.ActionList := ActMdiForm;
WindowMinimize.Caption := '';
WindowMinimize.ImageIndex := 0;
//将action与button关联
BtnMin.Action := WindowMinimize; //最小化
BtnMin.BringToFront;
BtnMin.Visible := false;

//建立恢复功能Button
BtnRestore := TMDIButton.Create(self);
BtnRestore.Visible := false;
BtnRestore.Parent := self;
BtnRestore.Width := 16;
BtnRestore.height := 15;
//建立恢复功能action
WindowRestore := TWindowRestore.Create(nil);
//指定其图标
WindowRestore.ActionList := ActMdiForm;
WindowRestore.Caption := '';
WindowRestore.ImageIndex := 1;
//将action与button关联
BtnRestore.Action := WindowRestore;
BtnRestore.BringToFront;
BtnRestore.Visible := false;
//设置按纽位置,位置保持在主界面上相对不变
SetMDIFormActionPos;
end;

procedure TFrmMain.ApplicationEvents1Idle(Sender: TObject;
var Done: Boolean);
var
show: boolean;
begin
//当前子窗体的状态为最大化时,显示三个按纽
show := (self.ActiveMDIChild <> nil) and (self.ActiveMDIChild.WindowState =
wsMaximized);
if assigned(BtnClose) and BtnClose.Visible <> Show then
BtnClose.Visible := Show;
if assigned(BtnMin) and BtnMin.Visible <> Show then
BtnMin.Visible := Show;
if assigned(BtnRestore) and BtnRestore.Visible <> Show then
BtnRestore.Visible := Show;
end;

//设置按纽的相对位置不变

procedure TfrmMain.SetMDIFormActionPos;
begin
if assigned(BtnClose) then
begin
BtnClose.left := Width - 26;
BtnClose.top := 6;
end;
if assigned(BtnRestore) then
begin
BtnRestore.Left := Width - 44;
BtnRestore.Top := 6;
end;
if assigned(BtnMin) then
begin
BtnMin.Left := Width - 60;
BtnMin.Top := 6;
end;
end;

procedure TFrmMain.FormResize(Sender: TObject);
begin
SetMDIFormActionPos;
end;

procedure TFrmMain.FormDestroy(Sender: TObject);
begin
//释放资源
if assigned(BtnClose) then
begin
WindowClose.ActionList := nil;
WindowClose.free;
BtnClose.Free;
BtnClose := nil;
end;
if assigned(BtnRestore) then
begin
WindowRestore.ActionList := nil;
WindowRestore.free;
BtnRestore.Free;
BtnRestore := nil;
end;
if assigned(BtnMin) then
begin
WindowMinimize.ActionList := nil;
WindowMinimize.free;
BtnMin.Free;
BtnMin := nil;
end;
end;

{ TWindowRestore }

procedure TWindowRestore.ExecuteTarget(Target: TObject);
begin
inherited;
with GetForm(Target) do
ActiveMDIChild.WindowState := wsnormal;
end;

{ TMDIButton }

procedure TMDIButton.wndproc(var message: Tmessage);
begin
if message.msg = wm_SetFocus then exit;
inherited wndproc(message);
end;

{ TWindowMinimize }

procedure TWindowMinimize.ExecuteTarget(Target: TObject);
begin
inherited;
with GetForm(Target) do
ActiveMDIChild.WindowState := wsMinimized;
end;

procedure TFrmMain.open1Click(Sender: TObject);
begin
with Tform.create(self) do
begin
formstyle := fsMDIChild;
end;
end;

end.