View Code
using System;
using System.Collections.Generic;
using System.Linq;
public class StudyLinq3
{public static void Main(){List<Student> list = new List<Student>();list.Add(new Student(){Age=10,Name="Jack",Address="bj"});list.Add(new Student(){Age=67,Name="Mack",Address="郑州"});list.Add(new Student(){Age=23,Name="Dack",Address="USA"});list.Add(new Student(){Age=56,Name="Cack",Address="bj"});list.Add(new Student(){Age=8,Name="Eack",Address="郑州"});list.Add(new Student(){Age=34,Name="Hack",Address="bj"});list.Add(new Student(){Age=18,Name="小红",Address="USA"});var result = ( from p in listwhere p.Age >30select p).OrderByDescending(pp=>pp.Age);foreach(Student s in result){Console.WriteLine(s.Age);    }/*string[] str = {"a","bb","abc","中华民谣","USA"};IEnumerable<string> result = from p in strwhere p.Length>3select p;foreach(string s in result){Console.WriteLine(s);    }IEnumerable<string> result = str.Where<string>(p=>p.Length>3);foreach(string s in result){Console.WriteLine(s);    }*/}
}public class Student
{public int Age{get;set;}public string Name{get;set;}public string Address{get;set;}
}

View Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Security.AccessControl;
namespace StudyIO
{class Program{static void Main(string[] args){// Directory.CreateDirectory("d:\\ss");//string[] strs = Directory.GetFiles("d:\\mp3");//foreach (string str in strs) //{//    Console.WriteLine(str);//}string[] strs = Directory.GetFileSystemEntries("e:\\ftppublish");foreach(string s in strs){if (Directory.Exists(s)) {string[] ss = Directory.GetFileSystemEntries(s);foreach(string fs in ss){Console.WriteLine(fs);}}}}static void Test8() {Stream streams = File.Open("D:\\1.cs", FileMode.Open);Stream streamw = File.Open("D:\\1.cs", FileMode.Open);BufferedStream stream = new BufferedStream(streamw);// stream.Write();//   stream.Read();
        }static void Test7() {FileStream stream = File.Open("d:\\1.cs", FileMode.Open);BinaryReader reader = new BinaryReader(stream);byte[] buffer = new byte[1024];int i = 0;string str = "";while ((i = reader.Read(buffer, 0, buffer.Length)) != 0){str += Encoding.UTF8.GetString(buffer, 0, i);}reader.Close();stream.Close();Console.WriteLine(str);}static void Test6(){//FileStream stream = File.Open("D:\\1.cs", FileMode.Append);//StreamWriter writer = new StreamWriter(stream);//writer.Write("你好");//writer.Close();// Test5();
        }static void Test5() {//只是单独操作字符StreamReader reader = new StreamReader("d:\\1.cs",Encoding.UTF8);//先读string str = reader.ReadLine();while (str != null){Console.WriteLine(str);str = reader.ReadLine();}reader.Close();}static void Test4() {//1，读源文件FileStream read = File.Open(@"E:\FTPPUBLISH\学习资料\[电影天堂-www.dy2018.net]龙门飞甲.720p.HD中文字幕.rmvb", FileMode.Open);long count = read.Length;//2，写文件FileStream write = File.Open("d:\\23.rmvb", FileMode.OpenOrCreate);byte[] buffer = new byte[1024 * 1024 * 4];int i = 0;int r = 0;while ((i = read.Read(buffer, 0, buffer.Length)) != 0){r = r + i;string s = (((double)r / count) * 100).ToString("0.00") + "%";Console.WriteLine(s);write.Write(buffer, 0, i);}write.Close();read.Close();}static void Test3() {FileStream fs = File.Open("d:\\1.cs", FileMode.Open);//默认缓冲区为1024,每次从文件（文件流）读1024个字节byte[] buffer = new byte[1024];//当程序读文件的收，把读取的自己从缓冲流的第一个元素开始放。//已经读取的字节数，如果i=0的话，说明已经读取到末尾了，从而结束循环int i = 0;string result = "";while ((i = fs.Read(buffer, 0, 1024)) != 0){Console.WriteLine(i);result += Encoding.UTF8.GetString(buffer, 0, i);}fs.Close();Console.WriteLine(result);}static void Test2() {//写操作FileStream fs =  File.Open("d:\\1.cs",FileMode.Open);//向文件中写内容string str = "这是C#的IO操作";byte[] buffer = Encoding.UTF8.GetBytes(str);fs.Write(buffer,0,buffer.Length);fs.Close();}static void Test() {//File.Create("d:\\1.cs");//File.Copy("d:\\12.mp3", "E:\\刀剑如梦.mp3");//File.Delete("E:\\刀剑如梦.mp3");//File.Move("d:\\12.mp3", "E:\\刀剑如梦.mp3");//  FileAttributes fa = File.GetAttributes("E:\\刀剑如梦.mp3");// Console.WriteLine(fa);//  DateTime dt = File.GetCreationTime("E:\\刀剑如梦.mp3");// Console.WriteLine(dt.ToString());
        }}
}