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Borland C++ Builder control array events

Having created a control array in Borland C++ Builder, how does one access the control which has generated a message.

// declarations
#define NUM_IMG 10
TImage * image[NUM_IMG];
void __fastcall MyClick(TObject* Sender);

// construction of the array, where Image1 is a design time image with bitmap loaded.
for(int i = 0; i < NUM_IMG; ++i)
{
image[i] = new TImage(sbPictureScrollBox);
image[i]->Parent = sbPictureScrollBox;
image[i]->Picture = Image1->Picture;
image[i]->AutoSize = true;
image[i]->Top = i * 10;
image[i]->Left = 10;
image[i]->Visible = true;
image[i]->Invalidate();

image[i]->OnClick = MyClick;
}

In the implementation of the event handler MyClick, how do I find out which control has generated the event?

DrDelphi

Add a line to include a Tag for each TImage:

image[i]->Tag=i;

Next in the MyClick routine query that tag's value:

void __fastcall TForm1::MyClick(TObject *Sender)
{
if (dynamic_cast<TImage*>(Sender)!=NULL);
ShowMessage(dynamic_cast<TImage*>(Sender)->Tag);
}

Good luck!!

thienpnguyen

The control that has generated the event is sender argument in method
void __fastcall MyClick(TObject* Sender);

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thienpnguyen

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lirtua

ASKER

Your answer is good. It made me realize what Sender is. (something the borland help files fell short of) And so, here is my choice of implementation:

void __fastcall TfrmMain::MyClick(TObject* Sender)
{
// get the control
// ok since this method is only for the image array
TImage* img = (TImage*)Sender;

// mess with it
img->Left += 10;
}