Retrieving data from a property

Question

Hi Given the following code I came across:- ConsoleKeyInfo cki; cki = Console.ReadKey(); Console.WriteLine(Key pressed: {0}
 cki.Key); if (cki.Key == ConsoleKey.X) break; My question is how is the Key property holding the required data without even being set? The only thing I can see happening is that the instance variable cki is storing the return value captured from the ReadKey method. Id usually expect to see the something like:- ConsoleKeyInfo cki = new ConsoleKeyInfo(); cki.Key = Console.ReadKey(); Console.WriteLine(Key pressed: {0}
 cki.Key); Regards Steven

Vulpes · Answer

This line: cki = Console.ReadKey(); is creating a ConsoleKeyInfo structure and storing it in the memory slot reserved for the local variable cki on the stack. So cki actually contains the structure rather than a reference to where it's stored elsewhere in memory. Whilst you're right that structures aren't objects the terms 'instance' and 'instantiation' can be (and often are) used when creating either of them.

S · Answer

Understood many thanks Vulpes

S · Answer

And by the line:- Is automatically set when the ConsoleKeyInfo structure is instantiated. Is this referring to ConsoleKeyInfo cki; cki = Console.ReadKey(); I thought instantiatation was creating a new object?

Vulpes · Answer

The Console.ReadKey() method returns a ConsoleKeyInfo structure which contains details of the key pressed. In particular it has a read-only Key property which returns a ConsoleKey value. This (or to be more precise the underlying field) is automatically set when the ConsoleKeyInfo structure is instantiated. ConsoleKey is an enumeration which has values for every key on the keyboard. For a list see here: http://msdn.microsoft.com/en-us/library/system.consolekey.aspx