#701 – Centralize Business Rules Logic in set Accessors

You can use a property’s set accessor to enforce business rules for that property, e.g. min/max values for the property.

If you have a constructor that accepts initial values for some properties of a class, or methods that accept values, you can avoid checking constraints on these parameters by delegating the enforcement of the rules to the set accessor.

For example:

    public class Dog
    {
        // Public properties
        public string Name { get; set; }

        private int age;
        public int Age
        {
            get { return age; }

            // Set accessor checks for valid Age values
            set
            {
                if (value != age)
                {
                    if ((value > 0) && (value < 30))
                        age = value;
                    else
                        throw new Exception("Age is out of range");
                }
            }
        }

        // Constructor
        public Dog(string name, int age)
        {
            Name = name;

            // Don't validate age value here, but let set accessor do it
            Age = age;
        }
    }
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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 #701 – Centralize Business Rules Logic in set Accessors

  1. that’s one of the worst practices ever. they are called accessors for a reason. I expect nothing more than accessing fields. code like that makes me cry. when the style cope even recommends such a style, create a setter instead of method with void arg, then it really makes me wish to drop from the C# bang wagon!

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