MDIChild closes MDIChildren

[Ed Dressel]

Several things to note:

MDIChildCount is the property of the main form. The current form
also has the property MDIChildCount--but it doesn't have any children.
Therefore, MDIChildCount is always zero. Change the code (also note the
different order of the loop) to:

For I := MainForm.MDIChildCount -1 to 0 do // MainForm is needed, also
reverse the loop order
if MainForm.MDIChildren[i] is Self then //you could try 'self' here
MainForm.MDIChildren[I].Close;

Ed Dressel

Wasis Sugiono wrote:

> Can a child form close other child forms (of MDIMain) ?
>
> Here's the code. But other child forms can not be closed.
>
> procedure TProperties.Button2Click(Sender: TObject);
> begin
>
> {Close all the windows except this one}
> {MDIChildCount is always 0}
> For i := 0 to MDIChildCount - 1 do
> If not (MDIChildren[i] is TProperties) Then
> MDIChildren[i].Close;
> End;
>
> Could u tell me what's wrong with it?
>
> Thanks in advance.

[Wasis Sugiono]

[Wasis Sugiono]

> MDIChildCount is the property of the main form. The current form
> also has the property MDIChildCount--but it doesn't have any children.
> Therefore, MDIChildCount is always zero. Change the code (also note the
> different order of the loop) to:
>
> For I := MainForm.MDIChildCount -1 to 0 do // MainForm is needed, also
> reverse the loop order

However if the order is forward, I get the same result. Does it sound
strange?

> if MainForm.MDIChildren[i] is Self then //you could try 'self' here
> MainForm.MDIChildren[I].Close;

It doesn't work.

[Ralph Friedman (TeamB)]

Wasis,

you need to use the MDIChildCount and MDIChildren properties of the MDIClient
form. e.g.:

procedure TProperties.Button2Click(Sender: TObject);
begin
with MDIClient do
begin

For i := 0 to MDIChildCount - 1 do
If not (MDIChildren[i] is TProperties) Then
MDIChildren[i].Close;

end;
End;

--
Regards
Ralph (TeamB)
--
Wasis Sugiono wrote in message <36DC4CB0...@rad.net.id>...

[Ralph Friedman (TeamB)]

Wasis,

you were supposed to substitute the name of _your_ MDI Client form for that.
Move "uses Main" to the implementation section and it will take care of the
circular reference.

--
Regards
Ralph (TeamB)
--

Wasis Sugiono wrote in message <36DD7A7D...@rad.net.id>...
|Ralph,

|
|
|> procedure TProperties.Button2Click(Sender: TObject);
|> begin
|> with MDIClient do
|> begin
|> For i := 0 to MDIChildCount - 1 do
|> If not (MDIChildren[i] is TProperties) Then
|> MDIChildren[i].Close;
|> end;
|> End;
|

|This doesn't work. It causes an error: "Undeclared indentifier: 'MDIClient' "
|
|I use this:
| For i := Main.MDIChildCount - 1 DownTo 0 Do
| If not (Main.MDIChildren[i] is TProperties) Then
| Main.MDIChildren[i].Close;
|
|This works but it's not good enough because I have to add:
|Uses
| Main
|
|Look, Main uses Properties and Properties uses Main. It's like a circular
loop.

[Wasis Sugiono]

Ralph,

> procedure TProperties.Button2Click(Sender: TObject);
> begin
> with MDIClient do
> begin
> For i := 0 to MDIChildCount - 1 do
> If not (MDIChildren[i] is TProperties) Then
> MDIChildren[i].Close;
> end;
> End;

This doesn't work. It causes an error: "Undeclared indentifier: 'MDIClient' "

I use this:
For i := Main.MDIChildCount - 1 DownTo 0 Do
If not (Main.MDIChildren[i] is TProperties) Then
Main.MDIChildren[i].Close;

This works but it's not good enough because I have to add:
Uses
Main

Look, Main uses Properties and Properties uses Main. It's like a circular loop.

I also have another question. This question is a reply to a message of
borland.public.delphi.winapi. It's about how to find out which MDI-Child is
opened.

Let's say I have a form THandOuts and the var is HandOuts. If there is one
instance of THandOuts, a new one can't be created.

procedure TMain.Handouts1Click(Sender: TObject);
begin
{Error: Incompatible types: TObject and Class reference}
If AlreadyExist(THandOuts) Then
Exit;

with THandouts.Create(self) do
Show;
End;

Function TMain.AlreadyExist (AnObject : TObject) : Boolean;
Var
i : Integer;
Begin
Result := False;

For i := 0 to MDIChildCount - 1 do

If MDIChildren[i] is AnObject then
Begin
MDIChildren[i].BringToFront;
Result := True;
Break;
End;
End;

procedure THandouts.FormClose(Sender: TObject; var Action: TCloseAction);
begin
Action := caFree;
end;

I don't know what's wrong with it. If I change the parameter's value become
HandOuts, the error is error no 405.

I think the problem is the parameter type.

Thanks

[Wasis Sugiono]

How about my next question?

[Ralph Friedman (TeamB)]

Wasis,

sorry, I hadn't scrolled down far enough to see it. Changing the declaration
to:

Function TMain.AlreadyExist (AForm: TForm): Boolean;

should do it for you.

--
Regards
Ralph (TeamB)
--

Wasis Sugiono wrote in message <36DD928C...@rad.net.id>...