How to handle the messages for controls which created at run time?

[hotcoffee]

How to handle the messages for controls which created at run time?

(Include windows stardard control and ActiveX control)

[Ravi Kiran]

Hi,


I guess, you mean 'events' raised from the controls?

Only way as i know is to have a member variable of the same type and use set

method when you create a run-time instance. The varibale should have a module-level (global) scope.


Ex: Suppose you have a control, StateChangingControl ,that raises some StateChanged(NewState,OldState) event.


To be able to handle this event you need something like this:


In the declaration section of Form/Class have a line:

private WithEvents m_mycontrol as StateChangingControl


and when you create a new runtime instance use:

...

set m_mycontrol = new StateChangingControl

...


With 'WithEvents' command, if VB detects any events associated with this StateChangingControl , it automatically lists them in the methods combobox.

You should see the member 'm_mycontrol' in the controls (LHS) combo (on the Editor)and when you select this, you should see the event 'StateChanged' in the methods (RHS) combo . And when you select 'StateChanged' from this list,

VB will create a stub like:


private sub m_mycontrol_StateChanged(NewState,OldState)

end sub

and the respective types of the params would also be present.


Try a simple code :

private withevents m_mytimer as Timer

and it would work like a timer-control of VB


I hope it was not a long answer for a not-required topic! :-)


Ravi