string readText = File.ReadAllText(@"c:\temp\MyTest.txt");

string[] readText = File.ReadAllLines(@"c:\temp\MyTest.txt", Encoding.UTF8);

byte[] buffer = File.ReadAllBytes(@"c:\temp\MyTest.txt");
string str = Encoding.Default.GetString(buffer, 0, buffer.Length);

using (StreamReader sr = File.OpenText(@"c:\temp\MyTest.txt"))
{
    string s;
    while ((s = sr.ReadLine()) != null)
    {
        Console.WriteLine(s);
    }
}

string createText = "Hello and Welcome" + Environment.NewLine;
File.WriteAllText(path, createText);//File.WriteAllText(），F(xiàn)ile.AppendAllText（）

string[] createText = { "Hello", "And", "Welcome" };
File.WriteAllLines(path, createText);

string str = "哈哈哈哈哈哈";
byte[] buffer = Encoding.Default.GetBytes(str);
File.WriteAllBytes(path,buffer);

using (StreamWriter sw = File.CreateText(path)) //StreamWriter:File.CreateText()、File.AppendText()
{
    sw.WriteLine("Hello");
    sw.WriteLine("And");
    sw.WriteLine("Welcome");
}

using (FileStream fs = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.None))
{
    byte[] b = new byte[1024];
    UTF8Encoding temp = new UTF8Encoding(true);

    while (fs.Read(b, 0, b.Length) > 0)
    {
        Console.WriteLine(temp.GetString(b));
    }
}

using (FileStream fs = File.OpenWrite(path))
{
    Byte[] info = new UTF8Encoding(true).GetBytes("This is to test the OpenWrite method.");

    // Add some information to the file.
    fs.Write(info, 0, info.Length);
}

using (FileStream fs = File.Create(path))
{
    Byte[] info = new UTF8Encoding(true).GetBytes("This is some text in the file.");
    // Add some information to the file.
    fs.Write(info, 0, info.Length);
}

//刪除此目錄
Directory.Delete(@"C:\新建文件夾")

//刪除此目錄，true表示要是此目錄有子目錄也刪除，否則就拋出異常
Directory.Delete(@"C:\新建文件夾", false);

//此目錄是否存在
bool b = Directory.Exists(@"C:\新建文件夾");

//根據(jù)路徑返回此目錄下的子目錄
string[] dirs1 = Directory.GetDirectories(@"C:\新建文件夾");

//第二個(gè)參數(shù)表示：搜索的范圍，就是搜索的文件夾包含“基礎(chǔ)”關(guān)鍵字
string[] dirs2 = Directory.GetDirectories(@"C:\新建文件夾", "基礎(chǔ)");

//搜索目錄下的所有文件
string[] files = Directory.GetFiles(@"C:\新建文件夾");

//第三個(gè)參數(shù)表示：指定搜索操作應(yīng)包括所有子目錄還是僅包括當(dāng)前目錄。
string[] files1 = Directory.GetFiles(@"C:\新建文件夾", "2.txt", SearchOption.AllDirectories);

//（獲取指定目錄下的所有目錄時(shí)返回一個(gè)DirectoryInfo數(shù)組。）
DirectoryInfo dirs = Directory.GetParent(@"C:\新建文件夾");

//移動(dòng)、剪切。只能在同一個(gè)磁盤中。目錄沒(méi)有Copy方法。可以使用Move()方法實(shí)現(xiàn)重命名。
Directory.Move(@"F:\測(cè)試\33", @"F:\測(cè)試\32\33");

//實(shí)例化FileInfo進(jìn)行操作
FileInfo myfile = new FileInfo(path); //聲明一個(gè)對(duì)象對(duì)某一個(gè)文件進(jìn)行操作
myfile.CopyTo(destpath);  //對(duì)文件進(jìn)行復(fù)制操作，復(fù)制路徑為destpath
myfile.MoveTo(destpath);  //進(jìn)行移動(dòng)操作
myfile.Delete();          //進(jìn)行刪除操作

//獲得某一文件或文件夾的詳細(xì)信息（創(chuàng)建日期，最后一次修改日期等等）
FileInfo myfile = new FileInfo(path); //聲明一個(gè)對(duì)象對(duì)某一個(gè)文件進(jìn)行操作
DateTime dt = myfile.CreationTime;  //獲取或設(shè)置文件/文件夾的創(chuàng)建日期
string filepath = myfile.DirectoryName; //僅能用于FileInfo,獲得完整的路徑名，路徑+文件名
bool file = myfile.Exists;              //此屬性的值表示文件或文件夾是否存在,存在會(huì)返回True
string fullname = myfile.FullName;     //獲取文件或文件夾的完整路徑名
DateTime lastTime = myfile.LastAccessTime; //獲取或設(shè)置最后一次訪問(wèn)文件或文件夾的時(shí)間
DateTime lastWrite = myfile.LastWriteTime; //獲取或設(shè)置最后一次修改文件夾或文件夾的時(shí)間
string name = myfile.Name;                 //獲取文件名，不能修改哦
long length = myfile.Length;                  //返回文件的字節(jié)大小
//CreationTime,LastAccessTime,LastWriteTime都是可以被修改的。

DirectoryInfo dir = new DirectoryInfo(@"d:\C#程序設(shè)計(jì)");
if (!dir.Exists)
{
    dir.Create();
}
else
{
    Console.WriteLine("該目錄已經(jīng)存在");
}

DriveInfo[] drivers = DriveInfo.GetDrives();
foreach (DriveInfo driver in drivers)
{
    if (driver.DriveType == DriveType.Fixed && driver.DriveFormat == "NTFS")
    {
        Console.WriteLine("在{0}驅(qū)動(dòng)器上還有{1}字節(jié)的剩余空間。", driver.Name, driver.AvailableFreeSpace);
    }
}