C # details about namespace

<1> The namespace hierarchy takes precedence over the namespace alias.
If this alias is the same as an existing namespace, you can use ":" to try the alias, which limits the alias namespace to be called.

using MyNamespace = ConsoleApplication19Namespace.MyNamespace2;namespace ConsoleApplication19Namespace{    class Program    {        static void Main(string[] args)        {            MyNamespace.Myclass My = new MyNamespace.Myclass();            My.print();            MyNamespace::Myclass You = new MyNamespace::Myclass();            You.print();        }    }    namespace MyNamespace    {        class Myclass        {            public void print()            {                Console.WriteLine("This is in the ConsoleApplication.MyNamespace.Myclass");            }        }    }    namespace MyNamespace2    {        class Myclass        {            public void print()            {                Console.WriteLine("This is in the ConsoleApplication.MyNamespace2.Myclass");            }        }    }}

Output:
This is in the ConsoleApplication. MyNamespace. Myclass
This is in the ConsoleApplication. MyNamespace2.Myclass


<2> global namespace
Global and ":" use the alias of the top-level root namespace together with globale:. Calling the top-level root namespace can prevent external variables or external classes from being internal variables, the appearance of hidden internal classes.
For example:

Global: System. Console. WriteLine ("what a fuck day"); // No problem occurs.