#278 – Passing an Array by Reference

You can pass an array by reference to a method, using the ref or out parameter modifier, when you want the method to change the parameter to refer to a different array.

Here’s an example of a method that accepts an array and then overwrites the reference so that it points to a new array.

        public static void DoubleADogList(ref Dog[] list)
            Dog[] bigList = new Dog[2 * list.Count()];

            int i2 = 0;
            foreach (Dog d in list)
                bigList[i2++] = new Dog(d.Name, d.Age, d.Motto);
                bigList[i2++] = new Dog(d.Name + " Clone", d.Age, d.Motto);

            // Change original reference to refer to new list
            list = bigList;

We can call this method, passing it an array. When the method returns, the array variable points to the new (larger) array.

            Dog d1 = new Dog("Kirby", 13, "Chase balls");
            Dog d2 = new Dog("Jack", 17, "Bark");

            Dog[] list = new Dog[] { d1, d2 };

            Dog.DoubleADogList(ref list);



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.

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