Author: Jonas Bilinkevicius

I want to create a TToolBar that will have corresponding buttons to the MDI 
children in my form, so that the user can switch between the children by clicking 
on the buttons - not going through the MDI menu. How do I do that ? Adding a button 
on MDI child creation, deleting the button when the corresponding window is closed, 
respond to CTRL+TAB, CTRL+F4 messages and so on.

Answer:

I did something like this. In my mdi parent form, I have three public procedures:

procedure addwindow(Sender: TForm; const Str: string);
procedure delwindow(Sender: TObject);
procedure activatewindow(Sender: TObject);

In the child form's oncreate, ondestroy, onformactivate, I call the corresponding 
parent's method sending self as the parameter. I store sender in the toolbutton's 
tag property so I know which button corresponds to which child window.

The code looks like this (TXnewsFrame is the mdi parent form; Taskbar is my 
toolbar).

1   { str is window's caption }
2   
3   procedure TXnewsFrame.AddWindow(Sender: TForm; const Str: string);
4   begin
5     with TToolButton.Create(TaskBar) do
6     begin
7       AutoSize := true;
8       Left := TaskBar.Width;
9       Parent := TaskBar;
10      Style := tbsCheck;
11      Grouped := true;
12      AllowAllUp := false;
13      OnClick := TaskClick;
14      Caption := Str;
15      Hint := Str;
16      Tag := Integer(Sender); { store form in button's tag }
17      Down := true;
18    end;
19    TaskBar.Update;
20  end;
21  
22  procedure TXnewsFrame.DelWindow(Sender: TObject);
23  var
24    i: integer;
25  begin
26    with TaskBar do
27      for i := ButtonCount - 1 downto 0 do
28        if TForm(Buttons[i].Tag) = Sender then
29        begin
30          Buttons[i].Free;
31          break;
32        end;
33  end;
34  
35  procedure TXnewsFrame.ActivateWindow(Sender: TObject);
36  var
37    i: integer;
38  begin
39    with TaskBar do
40      for i := ButtonCount - 1 downto 0 do
41        with Buttons[i] do
42          if TForm(Tag) = Sender then
43          begin
44            Down := true;
45            break;
46          end;
47  end;
48  
49  { taskbar's onclick event handler }
50  
51  procedure TXnewsFrame.TaskBarClick(Sender: TObject);
52  var
53    F: TForm;
54    i: integer;
55  begin
56    if (sender is TToolButton) then
57    begin
58      F := TForm(TComponent(Sender).Tag);
59      with F do
60        if (F <> Self.ActiveMDIChild) or not Visible then
61        begin
62          BringToFront;
63          if WindowState = wsMinimized then
64            ShowWindow(Handle, SW_RESTORE);
65        end;
66    end;
67  end;