#1,208 – C# 6.0 – Auto-Property Initializers Can Be Any Expression

An auto-property initializer, used to initialize the value of an auto-implemented property, can be any expression.  This includes the result of a method call.

Below, we initialize the value of the SecretName property to a value returned by the static function generateSecreteName.

    public class Dog
    {
        public string Name { get; set; }

        // DogCreationTime is immutable
        public DateTime DogCreationTime { get; } = DateTime.Now;

        public string SecretName { get; } = generateSecretName();

        public Dog(string name)
        {
            Name = name;
        }

        private static string generateSecretName()
        {
            Random rand = new Random();
            int numLetters = rand.Next(4, 13);  // 4-12 characters
            string name = "";
            for (int i = 1; i <= numLetters; i++)
                name = name + (char)('a' + rand.Next(0, 26));

            return name;
        }
    }

#1,207 – C# 6.0 – Auto-Property Initializers for Read-Only Properties

Prior to C# 6.0, if you wanted a read-only (immutable) property, you’d typically use a read-only backing field that is initialized in the constructor, as shown below.

    public class Dog 
    {
        public string Name { get; set; }

        // DogCreationTime is immutable
        private readonly DateTime creTime;
        public DateTime DogCreationTime 
        {
            get { return creTime; }
        }

        public Dog(string name)
        {
            Name = name;
            creTime = DateTime.Now;
        }
    }

In C# 6.0, you can use auto-implemented properties to implement a read-only property.  You do this by using an auto-property initializer.  The result is much cleaner than the above example, where we had to explicitly declare a backing field.

    public class Dog
    {
        public string Name { get; set; }

        // DogCreationTime is immutable
        public DateTime DogCreationTime { get; } = DateTime.Now;

        public Dog(string name)
        {
            Name = name;
        }
    }