Board index » cppbuilder » how to set a owner of form???

2003-08-02 01:45:18 PM
cppbuilder56
hi,all:
In a dll, I write a form like below:
Tmyfrm* frm=new Tmyfrm(hwnd or TForm*)
frm->ShowModal() or frm->Show();
hwnd and TForm* are passed argument into dll.
this frm can be displaied, but there is a task button in windows taskbar. I
don't want to display it, how should I do to hide it from taskbar.
please help me? Thanks.
--
Regards for you.
Siney
 

"Siney San" < XXXX@XXXXX.COM >wrote:
correctly. When you allocate the form, you need to pass who
you want to be the owner:
Tmyfrm *frm = new Tmyfrm( the handle of the owner to be );
If you use:
Tmyfrm *frm = new Tmyfrm( this );
the form which allocates it will be the owner. This should clear up the problem.
~ JD
 

"JD" < XXXX@XXXXX.COM >дÈëÓʼþ news:3f2b5d3a$ XXXX@XXXXX.COM ...
yours, but the task button also be shown. eg:
extern "C" __declspec(dllexport)
int MyForm(HWND hwnd,TForm* frm)
{
Tmyfrm* frm=new Tmyfrm(frm); //new Tmyfrm(hwnd);
frm->ShowModal();
}
the frm form can be shown and embeded into the parent(owner), if i write
code like below:
Tmyfrm* frm=new Tmyfrm(NULL);
frm->ShowModal();
the frm form can be shown separetely, but there is taskbutton in the
taskbar, how should i do to hide this taskbutton in my way.
 

{smallsort}

"Siney San" < XXXX@XXXXX.COM >wrote:
not. Second, you have defined a parameter 'frm' AND a variable
frm. In this case, I'm uncertain of how the compiler will
treat the parameter. Third, you are assigning the Owner as
it's self.
Truth be told, I have never had a need to put a form in a dll
but I would think that it should look something like this:
extern "C" __declspec(dllexport)
int MyForm( HWND hwnd )
{
Tmyfrm *A_New_My_Form = new Tmyfrm( hwnd );
return reinterpret_cast<int>( A_New_My_Form );
}
and it would be used like this:
Tmyform *frm = NULL;
frm = (Tmyform*)MyForm( this );
if( frm ) frm->ShowModal();
delete frm;
Note that you may need to cast the return differently but I
don't think so. Also, if you use frm->Show(), you can't put
the delete in there and I'm uncertain what will happen in that
case. Although the new form will be destroyed when the Owner
of the form is destroyed, I don't know what will happen to
memory if the new form is created over and over because it's
not deleted.
object that is responsible for things like handling all of the
windows messaging while the Owner is responsible for freeing
it's resources apon destruction.
instead of 'this'.
~ JD
 

"Siney San" < XXXX@XXXXX.COM >wrote:
~ JD
 

Out of curiousity, what happens if you have MainForm as the Owner of
Form1, and then Form1 creates another child form (Form2) and uses itself
as the owner? In such an instance, is a taskbutton created, or not?
If so, then doesn't this make it a bit difficult if you have a
hierarchichal tree of forms? In the above example, if I close Form1,
then Form2 will close, but if both are set to MainForm as the Owner of
each, then closing Form1 will not close Form2.
Comments appreciated.
David Erbas-White
JD wrote:

David Erbas-White < XXXX@XXXXX.COM >wrote:
some bug in your code that causes it to behave that way.
been assigned to it when it is destroyed. To be clear, while
closing a form MAY lead to code that destroys it, the simple
act of closing it does not destroy it.
~ JD
 

JD wrote:
information). I generally have "Action=caFree" in my Close event, and
set the global form pointer to NULL in the Destroy event (I know, I
know, don't use Destroy, use the destructor, but this has been working
for me for eons, and I'm of the "if it ain't broke don't fix it" school).
Therefore, when I close a form, I am deleting it and freeing the memory.
Thus if MainForm creates Form1, and Form1 creates Form2, closing Form1
also closes (and frees) Form2.
David Erbas-White
 

David Erbas-White < XXXX@XXXXX.COM >wrote:
that that form has to be the Owner.
~ JD
 

David Erbas-White < XXXX@XXXXX.COM >wrote:
entire thread, the OP's code had issues that he didn't seem to
want to fix. He just wanted a 'one word' answer on how to not
show the new form on the taskbar using his existing code.
To that I replied to use the Main form as the Owner. Now, that
said, I googled a bit and it's the Parent - not the Owner that
effects how it appears on the taskbar.
So ... 20 lashes with a wet noodle for me.
~ JD
 

"JD" < XXXX@XXXXX.COM >дÈëÓʼþ news:3f2c2a47$ XXXX@XXXXX.COM ...
write code like below, but can't work fine.
in Exe
{
...
ShowMyForm(this,Handle); //this is my main form.
}
in Dll
ShowMyForm(TForm* parent,HWND hwnd)
{
Tmyfrm* frm=new Tmyfrm(parent); // or Tmyfrm* frm=new Tmyfrm(hwnd);
frm->ShowModal();
delete frm;
}
then, there is a taskbutton in the taskbar.
Anyone can tell me why?
 

David Erbas-White wrote:
Form1::OnCLose() Action is set to caFree;
Hans.
 

Hans Galema < XXXX@XXXXX.COM >wrote:
void __fastcall TForm2::CreateParams( TCreateParams& Params )
{
TForm::CreateParams( Params );
Params.ExStyle |= WS_EX_APPWINDOW;
Params.WndParent = GetDesktopWindow();
}
~ JD
 

Siney San wrote:
supply all the code I had to start from scratch.
Kent Reisdorph
Using a VCL form in a DLL
www.bridgespublishing.com/articles/issues/9809/Using_a_VCL_form_in_a_DLL.htm
or
tinyurl.com/iwbw
was a good start, and it was even easier as described there as the
myforms.lib was created by bcp3 compiling myforms.cpp.
Can only confirm what you say: there is an extra button in the
taskbar with a form from a dll.
Don't know the reason.
Then I did a google search in *cppbuilder* nesgroups for
DLL second taskbar
and found the problem reported many times.
A cause of this behaviour is described in
www.google.nl/groups&lr=&ie=UTF-8&oe=UTF-8&selm=37743655.45251718%40forums.inprise.com&rnum=4
or
tinyurl.com/iwcn
Hans.
 

The ariticle discussed the way that is static link, but my app must use
dynamic LoadLibrary to call form.
If can I set style of window to hide the button?