创建一个文件夹 用到的是Directory

Directory.CreateDirectory("./图书管理系统");
             //创建文件
             File.Create("./图书管理系统/暴走大事件.png");

读取文件信息

byte[] sByte=File.ReadAllBytes("./图书管理系统/1.png");
            File.WriteAllBytes("./图书管理系统/暴走大事件.png",sByte);

创建一个文件目录

DirectoryInfo dicInfo = new DirectoryInfo("./图书管理系统");
            dicInfo.Delete();//删除空目录

获取当前目录下文件结构 怎么获取目录下的所有文件

string[] files = Directory.GetFiles("./");//所有文件路径信息
            string pattern = @".+\.TXT$";//正则
            foreach(string i in files)
            {
                if (Regex.IsMatch(i, pattern))
                {
                    File.Delete(i);
                }
            }

获取的是该目录下的所有文件夹路径

string[] directories = Directory.GetDirectories("./");
            foreach(string i in directories)
            {
                Console.WriteLine(i);
            }

练习题1

使用学到的文件操作，创建三个文件文件名分别是数学.txt,语文txt英语tx,里面分别存放着50个学生的数学，语文,英语成绩，每一-行放着名字和对应的分数，名字是小明1, 小明2这样的规律显示，分数随机,每- -行显示的完整内容是科目+名字+分数，接下来用我们前面讲到的正则表达式，找出所有txt文件中的小明1的成绩逐行显示到1.txt文件中

StreamWriter fsWrite1 = new StreamWriter("./Math.TXT");
            StreamWriter fsWrite2 = new StreamWriter("./Chinese.TXT");
            StreamWriter fsWrite3 = new StreamWriter("./English.TXT");
            
            for(int i = 1; i <= 50; i++)
            {
                Random a = new Random();
                int num = a.Next(60,100);
                //Console.WriteLine("小明{0}，{1}",i,num);
                fsWrite1.WriteLine("数学,小明{0}，{1}", i, num);
            }
            for (int i = 1; i <= 50; i++)
            {
                Random a = new Random();
                int num = a.Next(60, 100);
                //Console.WriteLine("小明{0}，{1}",i,num);
                fsWrite2.WriteLine("语文，小明{0}，{1}", i, num);
            }
            for (int i = 1; i <= 50; i++)
            {
                Random a = new Random();
                int num = a.Next(60, 100);
                //Console.WriteLine("小明{0}，{1}",i,num);
                fsWrite3.WriteLine("英语，小明{0}，{1}", i, num);
            }
            
            fsWrite1.Close();
            fsWrite1.Dispose();
            fsWrite2.Close();
            fsWrite2.Dispose();
            fsWrite3.Close();
            fsWrite3.Dispose();

            StreamReader streamReader = new StreamReader("./Math.txt");
            StreamReader streamReader1 = new StreamReader("./Chinese.txt");
            StreamReader streamReader2 = new StreamReader("./English.txt");
            string s1 = streamReader.ReadToEnd();
            string s2 = streamReader1.ReadToEnd();
            string s3 = streamReader2.ReadToEnd();
            string[] sArray = s1.Split("\n");
            string[] sArray1 = s2.Split("\n");
            string[] sArray2 = s3.Split("\n");
            string patten = @"小明1";
            StreamWriter count = new StreamWriter("./1.TXT");
            foreach (string i in sArray)
            {
                if (Regex.IsMatch(i, patten))
                {
                    count.WriteLine(i);
                    break;

                }

            }
            foreach (string i in sArray1)
            {
                if (Regex.IsMatch(i, patten))
                {
                    count.WriteLine(i);

                    break;
                }

            }
            foreach (string i in sArray2)
            {
                if (Regex.IsMatch(i, patten))
                {
                    count.WriteLine(i);
                    count.Close();
                    break;

                }

            }