about window-owning control and non-window-owning control

[shanglinhu]

Q1:
I know Dialog is a window-owing control.Only one? else?
Q2:
I get codes from SDK, as follows:
CMyControl::ConstructL()
{
CreatWindowL(); //this makes the control window-owning
SetRectL(ClientRect());
ActiveL();
}
this code is an example of ow to construct a window-owning control,i know,but i am confused that where is the window-owning control? what's the meaning of "window-owning control"?

Q3:
A non-window-owning control must be contained within a window-owing control.
for example(from SDK):
CEikTextListBox* list=new (ELeave) CAknSingleStyleListBox();
list->ConstructL(this);
list->SetContainerWindow(*this);
......
list is a ListBox which belonged to non-window-owning control,
so it must be contained to a window-owning control,in the above code,what's a window-owning control? if i delete this sentence"list->SetContainerWindow(*this);",what will be happened?


thank u!
shanglinhu

[stenlik]

Hi,

a) each control must be assciated with window
b) control can own a window. By window i dont mean a GUI control, but class, which is associated with a control and managed by windows server, for example, when dialog dissapear the control below it redrawed - window server caring about overplapping, hidding windows...
c) window could be shared by many controls, which saves resources, on the clinet and server side. For example when 4 windows must be redrawed it costs much more resources and times when clinet-server communication is done. It is less expensive to use one bigger window. There are many window owning controls.
Example
Scrollbars in UIQ could be constructed as window floating above container controls or as a simple non-window control...
Bye
STeN