C#之Stream

1. .NET Framework provides Files and directories classes. 我们可以对文件或文件夹进行创建、移动、删除等操作，这些类与方法在System.IO里面。

2. IO里面的方法结构图

 

3. 注意：文件夹的方法全是静态的，所以不能创建实例调用而是直接用静态方法

4. 

Principal methods of the Directory class（文件夹类里面的基本方法）
Method	Use
CreateDirectory()	Creates all directories and subdirectories specified by its path parameter
GetCreationTime()	Returns and sets the time the specified directory was created
GetDirectories()	Gets named directories
GetLogicalDrives()	Returns the names of all the logical drives in the form <drive>:
GetFiles()	Returns the names of files matching a pattern
GetParent()	Returns the parent directory for the specified path
Move()	Moves a directory and its contents to a specified path

5. 而文件夹信息类可以得到文件夹里面的信息，例如子目录或文件夹里面的文件

Principal methods and properties of the DirectoryInfo class
Method or property	Use
Delete()	Public method that deletes a DirectoryInfo and its contents from the path
GetDirectories()	Public method that returns a DirectoryInfo array with subdirectories
GetFiles()	Public method that returns a list of files in the directory
GetFileSystemInfos()	Public method that retrieves an array of FileSystemInfo objects
MoveTo()	Public method that moves a DirectoryInfo and its contents to a new path
Refresh()	Public method inherited from FileSystemInfo; refreshes the state of the object

6. 文件类可以得到文件自身的内容和内容的性质

Principal public static methods of the File class
Method	Use
AppendText()	Creates a StreamWriter that appends text to the specified file
Copy()	Copies an existing file to a new file
Create()	Creates a file in the specified path
CreateText()	Creates a StreamWriter that writes a new  text file to the specified file
Delete()	Deletes the specified file
Exists()	Returns true if the specified file exists
GetAttributes(),  SetAttributes()	Gets or sets the FileAttributes of the specified file

7. 文件信息类可以得到文件所在的录目、名字等属性

Method or property	Use
Attributes()	Inherits from FileSystemInfo; gets or sets the attributes of the current file
CreationTime	Inherits from FileSystemInfo; gets or sets the creation time of the current file
Directory	Public property that gets an instance of the parent directory
Exists	Public property Boolean value that is true if the directory exists
Extension	Public property inherited from FileSystemInfo; that is, the file extension
FullName	Public property inherited from FileSystemInfo; that is, the full path of the file or directory

LastAccessTime	Public property inherited from FileSystemInfo; gets or sets the last access time
LastWriteTime	Public property inheritedfrom  FileSystemInfo; gets or sets the time when the current file or  directory was last written to
Length	Public property that gets the size of the current file
Name	Public property Name of this DirectoryInfo instance
AppendText()	Public method that creates a StreamWriter that appends text to a file
CopyTo()	Public method that copies an existing file to a new file

Create()	Public method that creates a new file
Delete()	Public method that permanently deletes a file
MoveTo()	Public method to move a file to a new location; can be used to rename a file
Open()	Public method that opens a file with various read/write and sharing privileges
OpenRead()	Public method that creates a read-only FileStream
OpenText()	Public method that creates a StreamReader that reads from an existing text file
OpenWrite()	Public method that creates a write-only FileStream

8. 对于文件的读写也有很多方法比如二进制读写等等 tips: 路径前面加@就可以少几个转义符

9. 当大量数据读写时，用buffer缓冲效率更高，同时为了保证数据的正确，需要进行校验