#271 – Passing a Reference Type as an Output Parameter

You can pass a reference-typed variable to a method as an output parameter, using the out keyword.  This indicates that the parameter is an output method.  For a reference type, this means that the method is expected to change the reference to point to a different object.

        public static void FindBallPlayingDog(out Dog fav)
        {
            fav = null;
            foreach (Dog d in AllDogs)
            {
                if (d.Motto.Contains("ball"))
                    fav = d;
            }
        }

When calling the method, we need to include the out keyword as a parameter modifier:

            Dog kirby = new Dog("Kirby");
            kirby.Motto = "Love chasing balls";

            Dog jack = new Dog("Jack");
            jack.Motto = "Sneak away when possible";

            Dog fav = jack;

            Dog.FindBallPlayingDog(out fav);   // Fav is now Kirby
Advertisements

About Sean
Software developer in the Twin Cities area, passionate about .NET technologies. Equally passionate about my own personal projects related to family history and preservation of family stories and photos.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: