combox box problem

[iiisecondcreep]

ok my problem is:
I have a combobox and 3 shapes (circle, square and ellipse)
Each of the shapes is listed in my combobox
When I select 'square' i need my square to appear and the other 2 to disappear
and likewise when I select circle, circle needs to appear and when I select ellipse i need ellipse to appear.
Now I've managed to do this with buttons, no problem!
(heres my button code for ellipse:
void __fastcall TForm1::EllipseButtonClick(TObject *Sender)
{
if (Ellipse->Visible == false);
{
Square->Visible = false;
Circle->Visible = false;
Ellipse->Visible = true;
}
}
)

But I just cannot work out the code for the combobox! I've tried my compilers help system but it really was no help at all!

I'm provided with this:
void __fastcall TForm1::ComboBox1Change(TObject *Sender)
for my combobox
and I believe I need to use this:
ComboBox1 = new TComboBox(this);

please help I am completely stumped!
also how do I change the colour of shapes? changing the colour of forms, no problem, but shapes?! HELP!

[Ivan**]

First explain exactly what you're trying to do with the combobox, if you want your combobox to display graphic images of a square, ellipse or circle then you should use csOwnerDraw style for your combobox and write the corresponding event handler.
To change the color of a shape use the TCanvas' Brush property like
Canvas->Brush->Color = clYellow;
Canvas->Ellipse(0,0,100,100); //the ellipse will be filled with yellow

[iiisecondcreep]

selecting a shape from the combobox dropdown menu should have the same effect as the buttons, the shape selected will appear if its not already visible.

I tried using the code with Canvas suggested but my compiler says square is not a member of TCanvas if i put it in OnStartDrag event (there is no onclick event)
if i put it in onmousedown, nothing happens
(the shapes want to change colour when the mouse button is clicked on them)

I am really regretting taking this course theres no way I'm gonna pass my final exam if I can't even get these simple things

[Ivan**]

If the code for button works there's no reason why it shouldn't work for the combobox.
void __fastcall TForm1::TComboBoxOnChange(TObject* sender)
{
if (ComboBox1->ItemIndex != -1) {//make sure the user selected an item
switch (ComboBox1->ItemIndex) {
case 0:
//draw circle
break;
case 1:
//draw ellipse
break;
case 2:
//draw square
break;
}
}

[iiisecondcreep]

Thanks that worked!
Now just to get those **** colours changing!