Extension Method:
[There is no hole
in my piggy bank but the money is still being inserted]
Extension Method is that kind of feature. Suppose we have a
base class Employee.
This class should not be modified but I need to insert some
methods in the Employee class.
No need for deriving the Employee class.
Now what is the solution?
The solution is Extension
Method. Extension methods enable you to add methods to existing types
without creating new derived type, recompiling or modifying the original type. Extension Methods are a special kind of
static method.
Example:-
I will add the following method to String class in my program
without derivation or modifying the String Class.
public static String
GetFirstThreeCharacters(this String str)
{
if
(str.Length < 3)
{
return
str;
}
else
{
return
str.Substring(0, 3);
}
}
Just I have to add a
static class like this .
public static class Extension
{
public static String
GetFirstThreeCharacters(this String str)
{
if
(str.Length < 3)
{
return
str;
}
else
{
return
str.Substring(0, 3);
}
}
}
Then I can use the GetFirstThreeCharacters in this manner in my Form Load Event.
private void Form1_Load(object
sender, EventArgs e)
{
String
st = "My Name is Arindam";
MessageBox.Show(st.GetFirstThreeCharacters());
}
