Extension Methods

Question 1

What is an extension method?

Answer 1

Extension methods enable you to “add” methods to existing types without creating a new derived type, recompiling, or otherwise modifying the original type.

Question 2

How to declare an extension method?

Answer 2

Via a static class with a static method. The method must has a this (only one, even for multiple params) keyword in the beginning.
e.g:
static public double ToDouble(this string data)

Question 3

What is a good place to store extension methods?

Answer 3

In its own namespace… e.g: Model.Employee.Extensions, or Your.Current.Namespace.Extensions

Question 4

Can an extension be called in a regular way (MyStaticClass.DoSomething(param))?

Answer 4

Yes… the static class reamains as is. Actually, the “this” keyword makes the static class an extension.

Question 5

How does visual studio diferentiate normal methods from extension methonds?

Answer 5

extension methods has a transparent box with down arrow.