已有定义的系统命令常数(感觉有些有问题):
SC_SIZE = 61440;
SC_MOVE = 61456;
SC_MINIMIZE = 61472;
SC_MAXIMIZE = 61488;
SC_NEXTWINDOW = 61504;
SC_PREVWINDOW = 61520;
SC_CLOSE = 61536;
SC_VSCROLL = 61552;
SC_HSCROLL = 61568;
SC_MOUSEMENU = 61584;
SC_KEYMENU = 61696;
SC_ARRANGE = 61712;
SC_RESTORE = 61728;
SC_TASKLIST = 61744;
SC_SCREENSAVE = 61760;
SC_HOTKEY = 61776;
SC_DEFAULT = 61792;
SC_MONITORPOWER = 61808;
SC_CONTEXTHELP = 61824;
SC_SEPARATOR = 61455;
SC_ICON = SC_MINIMIZE;
SC_ZOOM = SC_MAXIMIZE;
未定义的系统命令常数:
61441: 拖动左边框
61442: 拖动右边框
61443: 拖动上边框
61444: 拖动左上角
61445: 拖动右上角
61446: 拖动下边框
61447: 拖动左下角
61448: 拖动右下角
61458: 拖动标题栏
61558: 横向滚动条滚动
61574: 双击横向滚动条
61575: 纵向滚动条滚动
61559: 双击纵向滚动条
61587: 点击最小化图标
61490: 在非最大化时双击标题栏
61730: 在最大化时双击标题栏
//可能还有...
WM_SYSCOMMAND 是做什么的? 咱们先看看把 WM_SYSCOMMAND 消息封锁掉是什么样子吧:
代码文件:
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Label1: TLabel;
procedure FormCreate(Sender: TObject);
procedure FormDblClick(Sender: TObject);
protected
procedure WMSysCommand(var Message: TWMSysCommand); message WM_SYSCOMMAND;
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.FormCreate(Sender: TObject);
const
br = #13#10;
begin
Label1.AutoSize := True;
Label1.Caption :=
'此窗体屏蔽了 SYSCOMMAND 消息!' + br +
'将无法改变窗体大小;' + br +
'将无法移动窗体;' + br +
'将无法最大、最小化窗体;' + br +
'也将无法通过常规途径关闭窗体.' + br +
'' + br +
'所以提供了双击窗体关闭的功能.';
Label1.OnDblClick := OnDblClick;
end;
procedure TForm1.FormDblClick(Sender: TObject);
begin
Close;
end;
procedure TForm1.WMSysCommand(var Message: TWMSysCommand);
begin
// inherited; {取消这句的注释, WM_SysCommand 就活了}
end;
end.
窗体文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 172
ClientWidth = 264
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
OnCreate = FormCreate
OnDblClick = FormDblClick
PixelsPerInch = 96
TextHeight = 13
object Label1: TLabel
Left = 24
Top = 24
Width = 89
Height = 33
Caption = 'Label1'
end
end