Question

begginers question about C#.

In every program I have to include several namespaces, like:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

Why do I have to include:

using System.Collections.Generic;
using System.Linq;
using System.Text;

… since they are included with first one:

using System;

Thank you in advance!

Answer 1

Because nested namespaces are not included with parent one. See using directive documentation for details

A using directive does not give you access to any namespaces that are nested in the namespace you specify.