C# IO操作（一）Path类的常用方法

1.Path类，查看编译器可知，这个类是个静态的工具类，需要注意的是，这个类是对字符串的操作，与文件无关。

1)ChangeExtension()方法，修改文件的后缀（调用这个方法，如果给第二个参数制定为””，则表示移除扩展名）。

            //注意，C:\a\bb\ccc\ddd\1.txt这个不是一个真实存在的物理路径
             string sPath = Path.ChangeExtension(@"C:\a\bb\ccc\ddd\1.txt", "*.xls");
             Console.WriteLine(sPath);

运行结果如下:

aaarticlea/png;base64,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” alt=”” /> 

2）Combine()方法，路径的合并。

             string s1 = @"c:\a\b";
             string s2 = "c.doc";
             string fullPath = Path.Combine(s1, s2);
             Console.WriteLine(fullPath);

运行结果如下:

aaarticlea/png;base64,iVBORw0KGgoAAAANSUhEUgAAAHIAAAAdCAIAAAD5Ha+lAAAA80lEQVRoge2XUQrEIAxEvf+peoq9TH/2a8HaJM2osxWZ9yUS4vgilJZTEChvB9gTaaVw0foRk2i1FjEFaaUgrRSklcIiWo8fmxw0rhWN6NV7t52uYDmt5qjRlIE+aL+bd7QeFWYgb98r7qjPTC7ob+L1jw/tnEGjte4CdQyKk2bjo00X+ZxePbrOEmhFCV6B2RM1NXLVf6isgbQGjpo0yYjorcz+GRbSem/9qLVcH2kmYt8k0JwjWnsUQ5+sJLWmuzKzvql8nFyc09z38nh9hjws8juwG9JKQVopSCsFaaUgrRSklYK0UpBWCtJKQVopSCuDL1AAgWVC06pBAAAAAElFTkSuQmCC” alt=”” />

3）获取路径的目录部分和文件部分

            string path = @"C:\DRIVERS\WIN\AUDIO\SAII\SAII\CxHDAudioAPI.dll";
             Console.WriteLine(Path.GetDirectoryName(path)); //获取目录部分
             Console.WriteLine(Path.GetFileName(path));  //获取文件名
             Console.WriteLine(Path.GetFileNameWithoutExtension(path));  //获取文件名（不要扩展名）
             Console.WriteLine(Path.GetExtension(path));    //获取文件扩展名
             Console.ReadKey();

运行结果如下:

aaarticlea/png;base64,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” alt=”” />

4）获取指定文件的全路径（GetFullPath）

            string fullPath = Path.GetFullPath("1.txt");
             Console.WriteLine(fullPath);

运行结果如下:

aaarticlea/png;base64,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” alt=”” />

5)读取文件（ReadAllText，大文件不适用）

             string Msg = File.ReadAllText("1.txt");
             Console.WriteLine(Msg);

运行结果如下:

aaarticlea/png;base64,iVBORw0KGgoAAAANSUhEUgAAATQAAAAeCAIAAAAto3UsAAABEUlEQVR4nO3aUW6CQBiFUfa/qn8V3Uxf+tDaEoFhHCleyTlPZqL0g+TGxHT6BCJNrw4A1hknhDJOCPUzzg8gzN84JyCKcUIo44RQxgmhfsdZVVX1fTh/3VAzPecP0aPnSj0jnhln+83nP1w9emJ7RhinHj0n9IzoGWfNLK/Qf96+TuPjevS8e8+Iu3Eu/17jJhuHy/Pd66x+XI+ea/SM2P3m3LrJreit87GHq0fPNXpGdI6zcYWXPFw9et6rZ8RD41yNOORm6mb3/Xr05Pcc45kfhGqh//wuo//h6tGT33OMhP8Q+sfbG6KnTc9JEsYJrDBOCGWcEMo4IZRxQijjhFDGCaGME0IZJ4QyTghlnJDpCwrBa1KXzI88AAAAAElFTkSuQmCC” alt=”” />

6)获取临时目录

 Console.WriteLine(Path.GetTempPath());  //返回系统的临时文件夹路径

临时目录，很多软件都会用到，比方直接用解压软件打开一个压缩包（不是解压），那么看到的文件就会放在临时文件夹中。

GetTempFileName()  得到一个唯一的临时文件名，这个方法会在临时目录中创建一个0字节的文件。