//引入命名空间
using System;
using System.IO;
using System.Text;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            ReadCharacters();
        }

        static async void ReadCharacters()
        {
            StringBuilder stringToRead = new StringBuilder();
            stringToRead.AppendLine("Characters in 1st line to read");
            stringToRead.AppendLine("and 2nd line");
            stringToRead.AppendLine("and the end");

            using (StringReader reader = new StringReader(stringToRead.ToString()))
            {
                string readText = await reader.ReadToEndAsync();
                Console.WriteLine(readText);
            }
        }
    }
}

//引入命名空间
using System;
using System.IO;

class MainClass
{
    public static void Main() 
    {
        Object someObject = new StringReader("This is a StringReader");

        
        if (IsType(someObject, "System.IO.TextReader")) 
        {
            Console.WriteLine("GetType: someObject is a TextReader");
        }
    }
    public static bool IsType(object obj, string type) 
    {
        Type t = Type.GetType(type, true, true);

        return t == obj.GetType() || obj.GetType().IsSubclassOf(t);
    }
    
}