（WPF VB.Net）如何获取嵌套在TreeView中的Checkbox的状态？

I have a WPF window with a TreeView that contains a checkbox at each node. I want to be able to capture the state of the checkboxes but I don't know how. (I am trying to do this without writing much of the code in XML)I have a WPF window with a TreeView that contai