Check all checkboxes in a listview

I want to have a button that will check all checkboxes in my listview. I have:

Dim I as Integer
If listViewAccounts.CheckedItems.Count > 0 then

   (>>My Problem here<<)

End if

What to do next?

for i = 0 to listViewAccounts.Items.Count -1
   listViewAccounts.Items(i).Checked = true
next