C＃-文件I / O - 芒果文档

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📜 C＃-文件I / O

📅 最后修改于: 2020-12-28 05:11:53 🧑 作者: Mango

文件是具有特定名称和目录路径的存储在磁盘中的数据的集合。打开文件进行读取或写入时，它成为流。

流基本上是通过通信路径的字节序列。主要有两个流：输入流和输出流。输入流用于从文件读取数据(读取操作)，输出流用于写入文件(写入操作)。

C＃I / O类

System.IO命名空间具有各种类，这些类用于对文件执行大量操作，例如创建和删除文件，从文件读取或写入文件，关闭文件等。

下表显示了System.IO命名空间中一些常用的非抽象类-

Sr.No.	I/O Class & Description
1	BinaryReader Reads primitive data from a binary stream.
2	BinaryWriter Writes primitive data in binary format.
3	BufferedStream A temporary storage for a stream of bytes.
4	Directory Helps in manipulating a directory structure.
5	DirectoryInfo Used for performing operations on directories.
6	DriveInfo Provides information for the drives.
7	File Helps in manipulating files.
8	FileInfo Used for performing operations on files.
9	FileStream Used to read from and write to any location in a file.
10	MemoryStream Used for random access to streamed data stored in memory.
11	Path Performs operations on path information.
12	StreamReader Used for reading characters from a byte stream.
13	StreamWriter Is used for writing characters to a stream.
14	StringReader Is used for reading from a string buffer.
15	StringWriter Is used for writing into a string buffer.

FileStream类

System.IO命名空间中的FileStream类有助于读取，写入和关闭文件。该类派生自抽象类Stream。

您需要创建一个FileStream对象来创建一个新文件或打开一个现有文件。创建FileStream对象的语法如下-

FileStream  = new FileStream( , ,
   , );

例如，我们创建一个FileStream对象F来读取名为sample.txt的文件，如下所示–

FileStream F = new FileStream("sample.txt", FileMode.Open, FileAccess.Read,
   FileShare.Read);

Sr.No.	Parameter & Description
1	FileMode The FileMode enumerator defines various methods for opening files. The members of the FileMode enumerator are − Append − It opens an existing file and puts cursor at the end of file, or creates the file, if the file does not exist. Create − It creates a new file. CreateNew − It specifies to the operating system, that it should create a new file. Open − It opens an existing file. OpenOrCreate − It specifies to the operating system that it should open a file if it exists, otherwise it should create a new file. Truncate − It opens an existing file and truncates its size to zero bytes.
2	FileAccess FileAccess enumerators have members: Read, ReadWrite and Write.
3	FileShare FileShare enumerators have the following members − Inheritable − It allows a file handle to pass inheritance to the child processes None − It declines sharing of the current file Read − It allows opening the file for readin. ReadWrite − It allows opening the file for reading and writing Write − It allows opening the file for writing

Sr.No.

Parameter & Description

FileMode

The FileMode enumerator defines various methods for opening files. The members of the FileMode enumerator are −

Append − It opens an existing file and puts cursor at the end of file, or creates the file, if the file does not exist.
Create − It creates a new file.
CreateNew − It specifies to the operating system, that it should create a new file.
Open − It opens an existing file.
OpenOrCreate − It specifies to the operating system that it should open a file if it exists, otherwise it should create a new file.
Truncate − It opens an existing file and truncates its size to zero bytes.

FileAccess

FileAccess enumerators have members: Read, ReadWrite and Write.

FileShare

FileShare enumerators have the following members −

Inheritable − It allows a file handle to pass inheritance to the child processes
None − It declines sharing of the current file
Read − It allows opening the file for readin.
ReadWrite − It allows opening the file for reading and writing
Write − It allows opening the file for writing

例

以下程序演示了FileStream类的用法-

现场演示

using System;
using System.IO;

namespace FileIOApplication {
   class Program {
      static void Main(string[] args) {
         FileStream F = new FileStream("test.dat", FileMode.OpenOrCreate, 
            FileAccess.ReadWrite);
         
         for (int i = 1; i <= 20; i++) {
            F.WriteByte((byte)i);
         }
         F.Position = 0;
         for (int i = 0; i <= 20; i++) {
            Console.Write(F.ReadByte() + " ");
         }
         F.Close();
         Console.ReadKey();
      }
   }
}

编译并执行上述代码后，将产生以下结果-

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 -1

C＃中的高级文件操作

前面的示例提供了C＃中的简单文件操作。但是，要利用C＃System.IO类的强大功能，您需要了解这些类的常用属性和方法。

Sr.No.	Topic & Description
1	Reading from and Writing into Text files It involves reading from and writing into text files. The StreamReader and StreamWriter class helps to accomplish it.
2	Reading from and Writing into Binary files It involves reading from and writing into binary files. The BinaryReader and BinaryWriter class helps to accomplish this.
3	Manipulating the Windows file system It gives a C# programamer the ability to browse and locate Windows files and directories.