The foreach loop in C# executes a statement or a block of statements for each element in an instance of the type that implements the System.Collections.IEnumerable or System.Collections.Generic.IEnumerable interface. You don’t have to worry about how many elements are in the array, and you can be sure that you’ll get to use each one in the loop. We can use an example to show how this works. Perhaps the easiest example to use is that of an array, as shown below.

The array syntax is as follows:

• foreach (<baseType> <name> in <array>)

In the code below we have declared a variable called friendNames that is an array of strings, as indicated by string[]. We have used object initialization syntax to immediately initialize the array. In the foreach() loop the basetype is string. the name is friendName. The array is friendNames.

    class Program
    {
        static void Main(string[] args)
        {
            string[] friendNames = { "Jack", "Kevin", "Sally" };
            Console.WriteLine("Here are {0} of my friends:", friendNames.Length);
            foreach (string friendName in friendNames)
            {
                Console.WriteLine(friendName);
            }
            Console.ReadKey();
        }
    }

foreach gives you read-only access to the array contents, so you can’t change the values of any of the elements. In other words, if you try to assign a literal to any of the elements in the array within the foreach() loop, compilation fails.

Class Objects

We have another post where we create a Customer class and create a couple of objects, create a list of Customers that we iterate through using a foreach loop to display some properties. The code is in the post C# Lists of Class Objects.