Use of delegates and interfaces

Question

Hey... Can anybody please tell me what's the use of interfaces and delegates and when they should be used and any other stuff on them? thanks...

oblivion_lurks · Answer

sorry IFileExtension in the paragraph is suppose to be ICustomFile.

oblivion_lurks · Answer

if your very familiar with c++ then you will catch on to delegates very quickly. a delegate is an object that encapsulates a reference to a function. in c++ this would be called a function pointer. you would define a delegate like this... delegate void MyDelegate(); void DelegateTester () { MyDelegate md = new MyDelegate(TesterFunction); // call TesterFunction through the delegate object md md(); } // function that is called by the delegate void TesterFunction() { Console.WriteLine(Called by delegate!!); } all functions that wish to be ecapsulated in a delegate must exactally match the delegates return type and parameter type. delegates are mainly used in conjunction with events for notifications. i hope this helps!!

oblivion_lurks · Answer

whats up troublesome? try to picture this. you and your partner are creating a small project together. you both split up the work and divide it up into two main classes. you both realize that your classes implement two functions that perform similiar duties. your partner mentions inheriting from one or the other. you two think about it but soon realize inheriting wouldn't fit properly into the program logic. well you both want to implement the two functions but with out deriving. this is where interfaces come in. interfaces are similiar to abstract base classes. interfaces provide a way to reuse functions indexers properties ect and their signatures in other projects. the class that inherits from the IFileExtension interface must abide to the contract of the interface by implementing both methods. interfaces will always be public. as you can see i left out the public modifier for the interface and methods becuase the default is public. i really hope this made sense to you. let me know what you think!! ill respond to the delegate question in another reply to space out the reading. interface ICustomFile { void CreateCustomFile(); void AccessCustomFile(); } // your class // create a class to block deriving public sealed class KDLFileCreater : ICustomFile { // function that must be implemented public void CreateCustomFile() { ... } // function that must be implemented public void AccessCustomFile() { ... } } // your partner's class // create a class to block deriving public sealed class ZPMFileCreater : ICustomFile { // function that must be implemented public void CreateCustomFile() { ... } // function that must be implemented public void AccessCustomFile() { ... } }