C# 0 The Complete Reference

ref

: An argument passed by 

ref

 must 

be assigned a value prior to the call. The reason is that the method that receives such an 

argument assumes that the parameter refers to a valid value. Thus, using 

ref

, you cannot 

use a method to give an argument an initial value.

Use out

Sometimes you will want to use a reference parameter to receive a value from a method, but 

not pass in a value. For example, you might have a method that performs some function, 

such as opening a network socket, that returns a success/fail code in a reference parameter. 

In this case, there is no information to pass into the method, but there is information to pass 

back out. The problem with this scenario is that a 

ref

 parameter must be initialized to a 

value prior to the call. Thus, to use a 

ref

 parameter would require giving the argument a 

dummy value just to satisfy this constraint. Fortunately, C# provides a better alternative: 

the