C# 7 Features - Out Variable Initialization

In my previous article, I discussed about the concept of local functions in C# 7.0. In this article, we will see another feature related to the use of out type variables. 

 

Out variables are not new in C# and provide a big advantage of how we can return multiple values from a method. However, in order to pass an out type variable as a method parameter, we have to declare it first and then pass it into the method parameter with out keyword, which is shown below.

static void Main(string[] args)
{

            int userId;
            string userName;
            GetDetails(out userId, out userName);

            Console.ReadKey();
}
public static void GetDetails(out Int32 UserId, out string Username)
{
            UserId = 12;
            Username = "Test User";
}

However, in C# 7.0, we can declare the variable at the time of passing it as a method parameter, when the method is being called. This means the code given below will work fine in C# 7.0. 

static void Main(string[] args)
{
            GetDetails(out int userId, out string userName);
            Console.ReadKey();
}

Also, we can have the out variable being declared as of var type, when passed as method parameter. Hence, the code given below is valid and works fine in C# 7.0, which did not work in earlier versions of C#. 

static void Main(string[ ] args)
        {
            GetDetails(out var userId, out var userName);
            Console.ReadKey();
        }

I hope you enjoyed reading it. Happy coding.