What are delegates?
Delegates are object that refer to an method. Normally we refer to objects, however referring to an object isn’t any different from referring a method they too have physical location in memory.
Why use delegate?
One delegate can be used to call different methods during runtime of a program by simply changing the method to which the delegate refers.
and Delegates Support Events.
delegate ret-type name(paramerter-list);
e.g. delegate string MyDelegate();
The MyDelegate can call any method whose return type is string and accepts no parameter. It can be instance method or a static method.
delegate string MyDelegate(String s);
static string GetNameLower(String s)
return s.ToLower() ;
static string GetNameUpper(string s)
static void Main(string args)
MyDelegate myD = new MyDelegate(GetNameLower); //or myD=GetNameLower
string s1 = myD(“Hi Nishant”);
myD = new MyDelegate(GetNameUpper); //or myD=GetNameUpper
string s2 = myD(“Hi Nishant”);
We can have chain of methods that will be called automatically when a delegate is invoked.
For this we will use += operator to add methods to chain and -= to remvove a method.
If delegate returns value than value returned by the last method becomes the return value of entire deleagation invocation. Thus a delegate making use of multicasting will have void as return type.
delegate void MyDelegate();
static void GetNameLower()
static void GetNameUpper()
static void Main(string args)
MyDelegate myD = GetNameLower;
myD(); //invoking the delegate
Static keyword can be applied to
Class, field, method, properties, operator, event and constructors.
Static member belongs to the class and not to any object of the class.
They can be used without creating the instance of the class.
For e.g. Static Void Main()
It is called by the operating system on program execution
To access the static member we’ll use
When a variable is declared as static internally what happens is that all the instances of the class share the same static variable. A static variable is initialized when its class is loaded. If not
initialized explicitly then
it is initialized to zero for numeric variable
null in case of object references
false for boolean
StaticMethod– they can only contain static member and call other static method.
If we need to access them than it can be done through the object of that class
public static void getNameThroughStatic(Game g)
g.getGameName(); // accessing static method
When to use them?
Well we can use them when we need to maintain information applicable to the entire class
suppose we have a class Employees there we can have a static count variable to keep track of no of employees.
static in count=0;
What are Static Constructor?
They can be used to initialize the static variables.
They are called automatically and before the instance constructor (if called any).
for above class
static Employees() // no other access modifiers for them
What are static Classes?
A class whose objects can’t be created and which can only have static members. They can’t be inherited as well.
They can have static constructor
Why use static Classes?
It can be used to group related static method.