Question

How do you use the “using” statement in C#?

Answer 1

There are two ways to use the using keyword in C#. One is as a directive and the other is as a statement. Let's explain!

1. using Directive 
   Generally, we use the using keyword to add namespaces in code-behind and class files. Then it makes available all the classes, interfaces and abstract classes and their methods and properties on the current page. Adding a namespace can be done in the following two ways:

2. Using Statement 
   This is another way to use the using keyword in C#. It plays a vital role in improving performance in Garbage Collection.