Using value, valuechanged, valueexpression with multiple

[abbottmw]

I am trying to switch to use the Value, ValueChanged and ValueExpression but with a list of items, not a single item. I need to do something when the Value changes.

This example is similar to what I'm doing but im binding with a list of items selected not a single one. It looks like I need to use TItem and TValue possibly?

I'm missing something silly I assume. I am not sure what types i need to specify in the T Value and item.

Example