Generic Delegates

To confuse matters even more, or should that be to confer further elegance and power, you can also create generic delegate types. Put simply, you can use a generic type anywhere within a delegate definition. For example:

delegate int HelloType<T>(T param);

creates a delegate type with a generic parameter.

To use the delegate you have to provide the type information. For example:

HelloType<int> HelloInst = new HelloType<int>(hello);

where Hello is a method which returns an int and has a single int parameter. You can also use the shorter:

HelloType<int> HelloInst = hello;

Before you start to invent clever ways of creating generic delegates for every purpose, I should warn you that, in the main, generic delegates should only be used within generic classes. In this context they provide a way to create delegate instances that “fit in” with the functioning of the entire delegate class. For example, you might create a delegate as a notification or event method which can be customized to work with the same data types as the rest of the generic class.

Postlude

Delegates are a central part of the .NET framework, but since .NET 2.0 it has been possible to save some typing and avoid unnecessary names by using anonymous, as opposed to named, methods. However as of .NET 3.5 anonymous methods have been overshadowed by lambda expressions. In both cases you can simply treat the new facilities as easier ways of defining a delegate. Anonymous methods are covered in depth in Chapter 14 together with lambda expressions. Also of interest is the way anonymous methods and lambda expressions enforce the adoption of closure, which is also discussed in that chapter.

Deep C#

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 Chapter List

1. Why C#?
   I Strong Typing & Type Safety
2. Strong Typing
      Extract  Why Strong Typing
3. Value & Reference
4.    Extract Value And Reference
5. Structs & Classes
      Extract Structs & Classes 
6. Inheritance
      Extract Inheritance
   
7. Interfaces & Multiple Inheritance
      Extract Interface
   
8. Controlling Inheritance
   II Casting & Generics
9. Casting - The Escape From Strong Typing
      Extract Casting I
   
10. Generics
11. Advanced Generics
12. Anonymous & Dynamic
    Typing III Functions
13. Delegates ***NEW!
14. Multicast Delegates
15. Anonymous Methods, Lambdas & Closures
    IV Async
16. Threading, Tasks & Locking
17. The Invoke Pattern
18. Async Await
19. The Parallel For
    V Data - LINQ, XML & Regular Expressions
20. The LINQ Principle
21. XML
22. LINQ To XML
23. Regular Expressions
    VI Unsafe & Interop
24. Interop
25. COM
26. Custom Attributes
27. Bit Manipulation
28. Advanced Structs
29. Pointers 

Extra Material

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