基本用法

using System;
using BasicStuff = System;
using Sayer = System.Console;
using static System.Console;  //From C# 6

class Program
{
    public static void Main()
    {
        System.Console.WriteLine("Ignoring usings and specifying full type name");
        Console.WriteLine("Thanks to the 'using System' directive");
        BasicStuff.Console.WriteLine("Namespace aliasing");
        Sayer.WriteLine("Type aliasing");
        WriteLine("Thanks to the 'using static' directive (from C# 6)");
    }
}