Delphi: How to assign dynamically an event handler without overwriting the existing event handler? -


i need loop through components , assign event handler (for example dynamically assigning onclick event tbutton to

showmessage('you clicked on ' + (sender tbutton).name);

the problem in cases assigned tbutton onclick event.

is there way solve problem?

let's imagine have button1 harcoded onclick event handler is:

showmessage('this button1');

after "parsing" full event handler button1 becomes:

showmessage('this button1'); // design time event handler code showmessage('you clicked on ' + (sender tbutton).name); // runtime added

note: looking soliution allows me use tbutton without inheriting it.

you assignment of onclick before overwriting it, persist , use in new handler - chaining events.

something this:

  var original : tnotifyevent;    original := component.onclick;   component.onclick := newmethod;

and in newmethod:

  if assigned(original) original(sender);

you'll not want single original variable instead hold collection keyed on component.


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