Both are pretty similar - the only difference is that a variable you pass as an
out
parameter
doesn't need to be initialized, and the
method using the out parameter has to set it to something.
int a;
Item(out a);
int b;
Item(ref b);
Ref
parameters are for data that
might be modified,
out
parameters are for data that's an
additional output for the function (eg int.TryParse) that are
already using the return value for something.
For more detail information please visit the following link:
The out and ref Paramerter in C#
What is the difference between out and ref in C#?