学习 Message(22): WM_SYSCOMMAND 消息[六] : 系统菜单综合操作示例

本例效果图:

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代码文件:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs, StdCtrls;



type

  TForm1 = class(TForm)

    Button1: TButton;

    Button2: TButton;

    Button3: TButton;

    Button4: TButton;

    Button5: TButton;

    procedure Button1Click(Sender: TObject);

    procedure Button2Click(Sender: TObject);

    procedure Button3Click(Sender: TObject);

    procedure Button4Click(Sender: TObject);

    procedure Button5Click(Sender: TObject);

    procedure FormCreate(Sender: TObject);

  protected

    procedure WMSysCommand(var Message: TWMSysCommand); message WM_SYSCOMMAND;

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



{定义两个菜单命令 ID 常数, 自定义的此类常数应该小于 $F000, 因为系统使用的都大于这个数}

const

  MenuCmdID1 = 101;

  MenuCmdID2 = 102;



{添加}

procedure TForm1.Button1Click(Sender: TObject);

var

  h: HMENU;

begin

  {系统菜单句柄}

  h := GetSystemMenu(Handle, False);

  AppendMenu(h, MFT_STRING, MenuCmdID1, '新添加的菜单项');

end;



{插入}

procedure TForm1.Button2Click(Sender: TObject);

var

  h: HMENU;

begin

  h := GetSystemMenu(Handle, False);

  {这是插入在 "还原" 菜单(SC_RESTORE) 前面}

  InsertMenu(h, SC_RESTORE, MFT_STRING, MenuCmdID2, '插入的菜单项');

end;



{修改}

procedure TForm1.Button3Click(Sender: TObject);

var

  h: HMENU;

begin

  h := GetSystemMenu(Handle, False);

  ModifyMenu(h, SC_MOVE, MF_BYCOMMAND, SC_MOVE, '这是我改的');

end;



{删除}

procedure TForm1.Button4Click(Sender: TObject);

var

  h: HMENU;

begin

  h := GetSystemMenu(Handle, False);

  {这是删除的 "关闭" 菜单, 此时窗口的关闭按钮会变灰}

  DeleteMenu(h, SC_CLOSE, MF_BYCOMMAND);

end;



{恢复}

procedure TForm1.Button5Click(Sender: TObject);

begin

  GetSystemMenu(Handle, True);

end;



procedure TForm1.FormCreate(Sender: TObject);

begin

  Button1.Caption := '添加';

  Button2.Caption := '插入';

  Button3.Caption := '修改';

  Button4.Caption := '删除';

  Button5.Caption := '恢复';

end;



procedure TForm1.WMSysCommand(var Message: TWMSysCommand);

var

  h: HMENU;

  buf: array[Byte] of Char;

begin

  h := GetSystemMenu(Handle, False);

  case Message.CmdType of

    MenuCmdID1: begin

      GetMenuString(h, MenuCmdID1, buf, Length(buf), MF_BYCOMMAND);

      ShowMessage(buf);

    end;

    MenuCmdID2: begin

      GetMenuString(h, MenuCmdID2, buf, Length(buf), MF_BYCOMMAND);

      ShowMessage(buf);

    end;

  end;

  inherited;

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 191

  ClientWidth = 206

  Color = clBtnFace

  Font.Charset = DEFAULT_CHARSET

  Font.Color = clWindowText

  Font.Height = -11

  Font.Name = 'Tahoma'

  Font.Style = []

  OldCreateOrder = False

  OnCreate = FormCreate

  PixelsPerInch = 96

  TextHeight = 13

  object Button1: TButton

    Left = 48

    Top = 20

    Width = 75

    Height = 25

    Caption = 'Button1'

    TabOrder = 0

    OnClick = Button1Click

  end

  object Button2: TButton

    Left = 48

    Top = 51

    Width = 75

    Height = 25

    Caption = 'Button2'

    TabOrder = 1

    OnClick = Button2Click

  end

  object Button3: TButton

    Left = 48

    Top = 82

    Width = 75

    Height = 25

    Caption = 'Button3'

    TabOrder = 2

    OnClick = Button3Click

  end

  object Button4: TButton

    Left = 48

    Top = 113

    Width = 75

    Height = 25

    Caption = 'Button4'

    TabOrder = 3

    OnClick = Button4Click

  end

  object Button5: TButton

    Left = 48

    Top = 144

    Width = 75

    Height = 25

    Caption = 'Button5'

    TabOrder = 4

    OnClick = Button5Click

  end

end