Introduction:
In this article i am going to explain about how to use c# function pointer delegates and interfaces in windows forms.

Main:
Before stating this article,we must know what is delegates?

Delegates are function pointers,
Delegates are type-safe and object oriented,
Delegates hold references of one or more functions and invoke them as needed,
Delegates are dynamic and are declared at runtime,
Delegates can point a set of ordered functions,

for ex,

Delegate void sampledelegate (string a);   class DelegateClass { public void Welcome(string a) { return "This is delegates sample" }   }

Delegate instance encaptulates more than one method,and each of these is called callable entity,

sampledelegate delobj = new sampledelegate (DelegateClass.Welcome)

Interfaces:

Simply we can define interface as “Contract”.What are the classes and structs defined interfaces
are simply signed some contracts.

what is a contract? An interface contract is a guarantee by an object that it will support all of
the elements of its interface. This contract is created using the Interface keyword, which declares
a reference type that encapsulates the contract.

An interface can the following as members,

Events,Indexers,Methods,Properties,

Interface IsampleInterface { void Calculatevalue ()   }

all methods,events,properties are declared inside interfaces are considered as public,

For calling interface just inherit it,

class Implementer : IsampleInterface

Conclusion:
Hope this helps,
Happy Coding.