Method group conversions (delegates)

C# language feature:

Method group conversions (delegates)

applies to

delegate assignment

benefit

Simplifies the syntax used to assign a method to a delegate. Method group conversion allows you to assign the name of a method to a delegate, without the use new or explicitly invoking the delegate’s constructor.

how to use

Assign methods to delegates minimizing boilerplate. That is, allow compiler to infer delegate assignment from overloaded method group.

see also

Anonymous methods, Delegate inference

example:

    class Method_Group_Conversion_Example
    {
        List<string> StringList = new List<string>();

        void method_group_example()
        {
            StringList.Add("some string");
            // Note that ForEach expects a delegate and a 
            // lambda expression is provided. The
            // compiler unambiguously calls `System.Console.WriteLine(string)` 
            StringList.ForEach(str => System.Console.WriteLine(str)); 

            // even "simpler" way to write without lamda expression
            StringList.ForEach(System.Console.WriteLine);  // example of method group conversion
            // compiler determines based on type of List and method group which method
            // of the various overloaded System.Console.WriteLine methods to resolve to
            // as a string is passed in, method group resolves to `System.Console.WriteLine(string)`
            // by passing, for example System.Console.WriteLine(Char)	
         }
    }

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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