Re: [ROOT] Problem getting WidgetId

From: Valeriy Onuchin (
Date: Mon Jan 26 2004 - 14:05:31 MET

Hi Christian,

> Dear Rooters
> To get the id of TGButtons, I have always used:
>     if (id == -1) {
>        TGButton *btn = (TGButton*)gTQSender;
>        id = btn->WidgetId();
>     }

TGButton is derived from TQObject and TGWidget,
so the cast is correct and calling btn->WidgetId() is correct.

> This has always worked, but I can only find TGButton Ids.
> Now I would like to find the Ids of either TGButton or
> TGListBox. Since both inherit from TGWidget I wanted to do:
>     if (id == -1) {
>        TGWidget *wdg = (TGWidget*)gTQSender;
>        id = wdg->WidgetId();
>     }

You can  only do:  TGListBox *wdg = (TGListBox*)gTQSender
gTQSender is inherited from TQObject,  not from TGWidget.
So, casting TGWidget *wdg = (TGWidget*)gTQSender is not possible.
Even if you get non-zero wdg pointer, it can not be used and should
cause segementation violation when calling  TGWidget methods.

> Sorrowly, this is not possible, since the return id is
> always zero.
> Do you know how I can get the WidgetId from different
> widgets such as TGButton, TGListBox, etc?

gTQSender is inherited from TQObject, not from TGWidget.
What is a purpose of getting WidgetId? 

Regards. Valeriy

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