(C++ VCL) Event

'Something that can happen to a Control'.

Changing an Event at run-time

An OnClick Event is a pointer to a function (sometimes called a callback function), of type 'void __fastcall (TForm1::*)(TObject * Sender)'.

Like any pointer-to-function, you can change it at run-time, like the example code below:

__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
  Button1->OnClick = ClickOne;
  Button1->Click();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Timer1Timer(TObject *Sender)
{
  ++Timer1->Tag;
  if (Timer1->Tag % 2 ==0 )
  {
    Button1->OnClick = ClickOne;
  }
  else
  {
    Button1->OnClick = ClickTwo;
  }
  Button1->Click();
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ClickOne(TObject *Sender)
{
  Button1->Caption = "One";
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ClickTwo(TObject *Sender)
{
  Button1->Caption = "Two";
}
//---------------------------------------------------------------------------

'Event' links

C++ Builder
?C++ CLX

Code links

void

last edited (April 5, 2007) by bilderbikkel, Number of views: 1047, Current Rev: 4 (Diff)

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