Introduction to Objects and Classes in C#

static void Main(string[] args)
{
    Person Michael = new Person();
    Person Mary = new Person();

    // Specify some values for the instance variables
    Michael.Age = 20;
    Michael.HairColor = "Brown";
    Mary.Age = 25;
    Mary.HairColor = "Black";

    // print the console's screen some of the variable's values
    Console.WriteLine("Michael's age = {0}, and Mary's age = {1}",Michael.Age,
        Mary.Age);
    Console.ReadLine();
}

Here I created the same objects from the last example, except that I used only properties to access the variable instead of accessing it directly. Look at the following line of code

Michael.Age = 20;

When you assign a value to the property like that C# will use the set accessor. The great thing with the set accessor is that we can control the assigned value and test it; and maybe change to in some cases. When you assign a value to a property C# changes the value in a variable and you can access the variable's value using the reserved keyword value exactly as I did in the example. Let's see it again here.

set
   {
       if(value <= 65 && value >= 18)
       {
           age = value;
       }
       else
           age = 18;
   }

Here in the code I used if statement to test the assigned value because for some reason I want any object of type Person to be aged between 18 and 65. Here I test the value and if it is in the range then I will simply store it in the variable age. If it's not in the range I will put 18 as a value to age.