Detecting page refresh - like we used to do in .net - Page.IsPostBack()

HI all,

I have a plugin extension that gives me a set of records (from the database).

#set($Response = $MyExtension.MyMethod())

I am iterating this collection and displaying :

#foreach($item in Response)

$item

<br />

#end

----

For e.g.: The above code will display

item1

item2

item3

item4

Now, every time the page is refreshed, the list of items displayed is duplicated...:

-------

item1

item2

item3

item4

item1

item2

item3

item4

------

Note: The duplicate entries grow each time we do a page refresh.

Is there any way to detect and avoid this.?

Thank you.