Named and optional arguments

C# language feature:

Named and optional arguments

applies to

method parameters

benefit

Named arguments are useful in making method calls self-documenting and reduce dependence on a parameter’s position in the parameter list.

how to use

1) Named arguments - preceed argument passed with name of parameter and :
2) Options arguments - must come after required arguments, and have default assignments.

example:

        void PrintName(string lastname,  string firstname, bool lastnamefirst=true)
        {
            if (lastnamefirst)
                System.Console.WriteLine(lastname + ", " + firstname);
            else
                System.Console.WriteLine(firstname + " " + lastname);
        }

        void Use_of_Named_Arguments_Example()
        {
            PrintName(firstname:"Jeff", lastname: "Doe");  // note parameter order does not matter, optional argument is true
            PrintName(lastname:"Doe", firstname:"Jeff");  // both print "Doe, Jeff"
        }

C# articles

csharp v2 +

Anonymous methods * Co- and Contra-variance for delegates * Delegate inference * Generics * Getter and setter separate accessibility * Iterators * Method group conversions (delegates) * Nullable types * Partials * Static classes *

csharp v3 +

Anonymous types * Auto-Implemented properties * Expression trees * Extension methods * Implicitly typed local variables * Lambda expression * Object and collection initializers * Partial methods * Query expressions *

csharp v4 +

Generic co- and contravariance * Named and optional arguments *

csharp v5 +

Asynchronous methods * Caller info attributes *

csharp v6 +

A note for CSharp 6 and beyond * Allow await in catch and finally blocks * Auto property initializers * Default values for Read-only Auto-properties * Dictionary (index) initializers * Exception filters * Expression-bodied members * Import of static type members into namespace * Null propagator (null-conditional operator, succinct null checking) * String interpolation * nameof operator *

csharp v7 +

Binary literals * Deconstruction * Digit separators * Expression bodied constructors and finalizers * Expression bodied getters and setters * Generalized async return types * Local functions * Out variables * Pattern matching * Ref returns and locals * Tuples *

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