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C# 7 - Return multiple values from methods


It was a long-awaited feature to return multiple values from a method. Developers used collection variables such as Array, ArrayList or Generic List to return multiple values from methods. Now with Visual Studio 2017 and C# 7, you can easily return multiple values with the help of Tuples.

In this article, I am going to explain how tuples can be used in C# 7 onwards to return multiple values.

Consider the following code from the console application. The method GetDivisionResults accepts two parameters namely number and divisor and returns two integers that are quotient and remainder.

         static void Main(string[] args)
         {
             int number = 17;
             int devisor = 5;
             var result = GetDivisionResults(17, 5);
             Console.WriteLine("Quotient is " + result.Item1);
             Console.WriteLine("Remainder is " + result.Item2);
         }

        static (int, int) GetDivisionResults(int number, int divisor)
         {

            int quotient = number / divisor;
             int remainder = number % divisor;
             return (quotient, remainder);
         }

The following function definition defines a function that returns two integer values as tuples.

(int, int) GetDevisionREsults(int number, int devisor)

(int, int) – defines the return type of the method, which is a tuple contains two integers. I am not concerned about the logic of the application, but see how it returns two numbers.

return (quotient, remainder);

Cool! Right. Let us evaluate how we can access the return values.

Console.WriteLine("Quotient is " + result.Item1);

Console.WriteLine("Remainder is " + result.Item2);

As you can see the values returned are accessed by the relative position in the Tuple. But using .Item1, .Item2 etc. from Tuple variable is not friendly. Luckily C# 7 gives you an option to define the variable names in tuples. Consider the following example.

         static void Main(string[] args)
         {
             int number = 17;
             int devisor = 5;
             (int quotient, int remainder) = GetDivisionResults(17, 5);
             Console.WriteLine("Quotient is " + quotient);
             Console.WriteLine("Remainder is " + remainder);
         }

        static (int, int) GetDivisionResults(int number, int divisor)
         {

            int quotient = number / divisor;
             int remainder = number % divisor;
             return (quotient, remainder);
         }

The difference is very clear. The following statement defines the names for the returned values.

(int quotient, int remainder) = GetDivisionResults(17, 5);

Now you are no longer required to use .Item1 or .Item2. You can directly use the variable as follows.

Console.WriteLine("Quotient is " + quotient);

Console.WriteLine("Remainder is " + remainder);

This is a very cool feature that every programmer will love. Although I used only tuples with two variables, you can return more than two variables.

e.g. consider the signature of a method that returns first name, middle name and last name from a given name.

(string, string, string) GetNameParts(string fullname);

Note: If you are using .Net Framework 4.6.2 or earlier, you need to include the System.ValueTuple Nuget package, otherwise you will get the following error.

Predefined type 'System.ValueTuple`2' is not defined or imported

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You can find the ValueTuple Nuget package from Microsoft and install it.

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