What do we mean by Using Keyword?

Answer:

Using is just a convention or a short-cut method which allows us to access the classes in a namespace by referencing it once.So whenever we want use the classes or methods in them, we can avoid typing the entire namespace hierarchy.

For Example:-

Using System.Data;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Xml.Linq;