Changing textblock binding dynamically

I have loaded so many data over 20,000 into palette having tree, and I want to add a button to change the displayed field of all node without reloading the all data again.
Can I just change the binding field of node template dynamically?

Yes, you can: just call Model.setDataProperty to change each databound property that you want.

Remember to make all of the changes within a single transaction.