#610 – Lazy Evaluation in Property Get Accessors

One of the benefits in using a property in a class, rather than a public field, is that you can delay calculation of the property’s value until client code actually tries to read the value.

In the code below, we define a FullDogDescription property that is read-only.  The private backing variable is initialized to an empty string and we only calculate its value in the get accessor when someone tries to read the property’s value.

<pre>        private string fullDogDescription = "";
        public string FullDogDescription
        {
            get
            {
                // Generate full description the first time that
                // someone reads this property.
                if (fullDogDescription == "")
                    fullDogDescription = GenerateDogDescription();

                return fullDogDescription;
            }
        }

The benefit of doing this is that if the call to GenerateDogDescription takes some time, we don’t spend the time calculating a value until some piece of code actually needs a value.

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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.

One Response to #610 – Lazy Evaluation in Property Get Accessors

  1. Mikhail says:

    I prefer to write such code as one-liner:

    private string fullDogDescription = null;

    public string FullDogDescription
    {
    get { return fullDogDescription ?? ( fullDogDescription = GenerateDogDescription() ); }
    }

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