I am using Kinect v2 to capture the depth frames. I saw Kinect SDK 1.x codes in C++, they used this
BYTE depth = 255 - (BYTE)(256*realDepth/0x0fff);
I want to know, what is the purpose of this command and  do I need to use this also for Kinect v2?
If I have to use this, then my code is in C#.
I am getting error  in multiplying this 256*realDepth
Error: Operator '*' cannot be applied to operands of type int and unshort.  
For those who give downmark, please explain the reason for that
                        
That line of code is used to normalize depth values, which are coded in 11 bits in the C++ API. With that command, the 11-bit representation is converted in an 8-bit one, which allows to display the depth map as a grayscale image.
Anyway, you don't need to use that line of code if you are developing your application in C#, because the API can do it for you.