I created a ListView with a column of checkboxes that I wanted centred as below:

 

Sounds like it should be easy, but it's a bit more tricky than just setting the CheckBox.HorizontalAlignment="Center" in your CellDataTemplate (which is what I tried first) as you still end up with it left-aligned if you do that.

I stumbled upon this post by Ian Griffiths that explains how to do it. In a nutshell, the problem occurs because the CheckBox control above is actually the child of a ListViewItem container, whose default alignment is Left (which does seem a bit nuts). So, as Ian points out, if you override the ListView.ItemContainerStyle and set its HorizontalContentAlignment to Stretch you can then Center or Stretch your child controls correctly.