Mega Code Archive
Minimize-maximize-close components at runtime
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{
This program try to show something at least interesting about those components
on the form. You'll see that by the fact they're descendant of TWinControl they
can react like a Window. I mean they can be maximized, minimized and so on.
If you see a control that not respond to our commands it's because it doesn't
descend from TWinControl. I didn't try to deal with them. Well. I believe this
program is an open door to great ideas. There's a lot of components that could
take advantages of this to manipulate controls on the form. You know a long journey
starts on the first step. Here it is.
Show me anything great you could do out of these ideas.
Good work.
Babak Sateli
babak_sateli@yahoo.com
}
unit MessComps;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, Menus, ExtCtrls;
type
TMessing = class(TForm)
Menu: TMainMenu;
Options: TMenuItem;
Minimize: TMenuItem;
Restore: TMenuItem;
Hide: TMenuItem;
Show: TMenuItem;
N2: TMenuItem;
Close: TMenuItem;
Exit_: TMenuItem;
CloseProgram: TMenuItem;
Maximize: TMenuItem;
Memo: TMemo;
Move: TMenuItem;
ChangeSize: TMenuItem;
N1: TMenuItem;
N3: TMenuItem;
Target: TMenuItem;
procedure Procede(Sender: TObject);
procedure TargetClick(Sender: TObject);
end;
var
Messing: TMessing;
n: Integer;
AllOfThem: Boolean = True;
implementation
{$R *.DFM}
procedure TMessing.Procede(Sender: TObject);
var
n, Tag: Integer;
T: TComponent;
ParentClass: TClass;
OkToProcede: boolean;
Comando: Word;
HasTheFocus: Boolean;
begin
// As the menu itens do pratically the same thing we directed them all to here.
// Their tag properties are different so we could know who called us.
// Save this. We'll need it
Tag := (Sender as TMenuItem).Tag;
case (Sender as TMenuItem).Tag of
// Oh! You just click options but you're already here. You didn't choose one
// yet so exit.
0: Exit;
// Now we have the options. Change comando accordingly to reflect our option.
1: COMANDO := SW_MINIMIZE;
2: COMANDO := SW_MAXIMIZE;
3: COMANDO := SW_RESTORE;
4: COMANDO := SW_HIDE;
5: COMANDO := SW_SHOW;
6: COMANDO := SC_SIZE;
7: COMANDO := SC_MOVE;
8: COMANDO := SC_CLOSE;
9: Application.Terminate;
end;
// Now we know the command we are ready to procede..
// So we start looking for the components this form has.
for n := 1 to ComponentCount do
// Well componentCount starts with 1
begin
// but ComponentsList starts with 0 (zero) so we make some adjustment
T := Components[n - 1];
// Now we have the component in our T variable and can ask a few questions
ParentClass := T.ClassParent;
// We want to know its ClassParent.
OkToProcede := ParentClass = TWinControl;
// if it is descendant of TWinControl then it's ok to procede.
while (ParentClass nil) and (OkToProcede = False) do
begin
// Oh no! Not yet. Maybe it descends of a lower class that is
// descendant of TWinControl. So we keep going back in its "genealogical"
// tree to see if we can find TWinControl back there somewhere or get to nil.
OkToProcede := ParentClass = TWinControl;
ParentClass := ParentClass.Classparent;
end;
// if we got to nil and didn't find TWinControl then we have nothing to do
// this component doen't accept our kinda of commands.
if OkToProcede then
begin
// Does it has the focus?
HasTheFocus := (T as TWinControl).Focused;
// If not AllOfThem and not has the focus so we break to the next one.
if (not AllOfThem) and (not HasTheFocus) then Continue;
if Tag then
// There no SC_SIZE or SC_MOVE or SC_CLOSE command in here so we have to apart.
ShowWindow((T as TWinControl).Handle, COMANDO)
else
// CloseWindow((T as TWinControl).Handle ); Doesn't work. It minimize them.
// But this one bellow works. It's possible to show them after closed but
// the controls loose some of their properties. Methinks it's dangerous
(T as TWinControl).Perform(WM_SYSCOMMAND, COMANDO, 0);
end;
end;
end;
// Changing our target
procedure TMessing.TargetClick(Sender: TObject);
begin
if (Sender as TMenuItem).Tag = 40 then
begin
(Sender as TMenuItem).Caption := 'Target: the focused one';
(Sender as TMenuItem).Tag := 41;
AllofThem := False;
end
else
begin
(Sender as TMenuItem).Caption := 'Target: all components';
(Sender as TMenuItem).Tag := 40;
AllofThem := True;
end;
end;
end.
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