如何在WPF ListView GridView中显示不同的contextmenu ?

I have a ListView GridView with ListViewItems that represent different categories of items. I'd like to display a different ContextMenu for each category of item. I was hoping to do this using DataTemplates but I'm struggling. My TreeView has a DataTemplate per category and I can see how I can set a different ContextMenu for each there but I can't seem to get similar DataTemplates to work for my ListView. Am I barking up the wrong tree?I have a ListView GridView with ListViewItems t