#696 – Using a Static Property to Count Instances

A static property is a property that allows access to a data item that is shared across all instances of a class, as opposed to an instance property, where there is a separate copy of the data for each instance.

One common use for a static property is to count the total number of instances of a particular class.  In the example below, the static NumDogs property keeps track of the total number of Dog objects.

    public class Dog
    {
        // Name / Age properties go here

        // Instance constructor
        public Dog(string name, int age)
        {
            Name = name;
            Age = age;
            NumDogs++;
            Console.WriteLine(string.Format("Constructor, # dogs now = {0}", NumDogs));
        }

        // Finalizer
        ~Dog()
        {
            NumDogs--;
            Console.WriteLine(string.Format("Finalizer, # dogs now = {0}", NumDogs));
        }

        // Static properties
        public static int NumDogs { get; protected set; }
    }

If we do the following:

            Dog d = new Dog("Kirby", 15);

            Dog d2 = new Dog("Ruby", 2);
            d = d2;

            GC.Collect();

We get:

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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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