How to zoom in/out selected elements of MapControl ?

Hi everyone,

I have a mapcontrol that includes many elements: text, line.
I used this code to add elements into mapcontrol: pGraphicsContainer.AddElement(pElement, 0);

I can use zoom button to zoom in/out the mapcontrol, but how can I zoom in/out only seleted elements ?

Is there any buttons for this purpose in Arcgis ?

Thanks and regards,

Tai