Optional parameter in C#

Tutorialsrack 07/08/2022 C#

By default, each parameter of a method is required, but in C# 4.0, Microsoft introduces optional parameters. So in this post, you’ll learn what is an optional parameter in C#. And how can you create and use optional parameters in C#? 

What is Optional Parameter in C#?

In C# 4.0, an optional parameter was introduced. The optional parameter in C# is the way to specify the parameters that are required but with the default values. If you do not pass the argument value at the method calling time, then the method uses its default argument values which we specified in the optional parameter.

Here is an example of Optional Parameters in C#

Example: Optional Parameters

using System;

namespace Program
{
    public class Program
    {
        //Optional Parameter in c#

        static void MethodWithDefaultParameter(int value = 1, string name = "Default Value")
        {
            Console.WriteLine("value = {0}, name = {1}", value, name);
        }
        public static void Main()
        {
            // Omit the optional parameters.
            MethodWithDefaultParameter();

            // Omit second optional parameter.
            MethodWithDefaultParameter(4);

            // You can't omit the first but keep the second.
            // Method("Dot");

            // Classic calling syntax.
            MethodWithDefaultParameter(4, "Tutorialsrack");

            // Specify one named parameter.
            MethodWithDefaultParameter(name: "Satya Nadella");

            // Specify both named parameters.
            MethodWithDefaultParameter(value: 5, name: "Sundar Pichai");

            Console.ReadLine();
        }
    }
}

Named Argument in C#

In addition, to complement the optional parameters, it is possible explicitly to specify parameter names in method calls. It makes your code more readable and clean. By specifying the parameter name, you can reorder the parameters in the parameter lists of called methods

The only restriction is that named parameters must be placed after the unnamed parameters. Parameter names can be specified for both optional and required parameters and can be used to improve readability or arbitrarily to reorder arguments in a call.

I hope this article will help you to understand what is an optional parameter in C#. And how can you create and use optional parameters in C#?

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