I have three classes, of which two subclass the first:

class MyItem {}
class MyItemA : MyItem {}
class MyItemB : MyItem {}

I show MyItemA using a DataTemplate thus:

<DataTemplate x:Key="MyTemplate"
         x:DataType="vm:MyItem">
  <TreeViewItem>
    <Grid ContextFlyout="{StaticResource MyItemAMenuFlyout}"

Now I wish to also add MyItemB to the TreeView, whith the exact same structure (as set by the MyTemplate DataTemplate) but with another right-click menu.

How can I do this without copying the whole MyTemplate xaml to another and changing the ContextFlyout? I wish to reuse the DataTemplate I already have (it only references properties from the base class).