CheckedListBox selct all items...

Hi...

How i can select all items in a CheckedListBox on selction of a first CheckedListBox item...?

Items in CheckedListBox are as follows- 

'Selct All'

First Item

Second Item

Third Item

So on click of 1st CheckedListBox item(SelectAll), i want to select all items...How i can do this...?

Thanks in adavnce,

Vinay