Part IV

Question 1

What’s the diffference between trigger and data trigger in WPF?

Answer 1

Trigger can only work on dependency properties while data triggers can have binding to any .NET property

Question 2

What is a Freezable class? Where is it used?

Answer 2

A freezable class is mainly used in WPF. It’s a class that notifies about changes, it can be frozen - then it behaves as if it was immutable.

Question 3

Can freezable class be unfrozen?

Answer 3

No it can’t be unfrozen but clone method can invoked on it. It creates a deep modifiable copy of the object.

Question 4

How dependency property works? Why is it good?

Answer 4

It’s stored in static context of a dependency object. Only changed values are stored. It helps save memory.

Question 5

List OSI layers and internet layers

Answer 5

OSI: application, presentation, session, transport, network, data link, physical. Internet: application, transport, network, network interfaces.

Question 6

What is a test double?

Answer 6

It’s a generic name for all objects that are needed in tests and should behave as their real life counterpart only to facilitate testing (mock, fake object, dummy object)

Question 7

What is a memo? Where is it used?

Answer 7

A memo is a value that is already computed and is used during computation, for example recursive fibonnaci.