C# Fundation, Part 3 (Passing Parameter by Value or by Reference)

 

Reference Type passed by Value

#1

#2

 

Reference Type passed by Reference (ref keyword)

#1

#2

 

If Both Reference Type & Value Type passed by Value

If Both Reference Type & Value Type passed by Value, but new an instance

If Reference Type passed by Reference

If Value Type passed by Reference

If Value Type passed by Reference using ref keyword

If Value Type passed by Reference using out keyword

If Value Type passed by Reference using ref keyword, but no initial value assignment of variable

Compile error: Use of unassigned local variable xxx

ref & out keyword has following difference

1. ref must have initial value assignment before passing to method, if not we will see the error

2. out must change its value within the method implementation, if not we will see the error

 

Blog to read:

http://rapidapplicationdevelopment.blogspot.tw/2007/01/parameter-passing-in-c.html

http://www.dotblogs.com.tw/hunterpo/archive/2010/05/02/14978.aspx (in Chinese)