What does this c# syntax mean?

Question

Hi I have a little problem with understanding this kind of syntax

public delegate void DelegateType();
BeginInvoke(new DelegateType(functionName));

Could somebody tell me what exectly mean new DelegateType(functionName). Why do I have to use new keyword ??

Answer 1

See the documentation.

A delegate is a type that holds a method.
You're creating a new instance of a delegate type, pointing to an existing method.

C# 2 adds an implicit conversion from a method group to any matching delegate type.
However, since BeginInvoke doesn't take a specific delegate type (such as System.Action), you always need to explicitly create a delegate instance.

Answer 2

The first statement declares a delegate type, the second statement instantiates a new delegate of DelegateType.

From the corresponding MSDN article (read the article for more information!):

Once a delegate type has been declared, a delegate object must be created and associated with a particular method. Like all other objects, a new delegate object is created with a new expression. When creating a delegate, however, the argument passed to the new expression is special — it is written like a method call, but without the arguments to the method.