Data read / write: realize data read / write function based on C ＃ script in unity

FileStream File stream

FileStream Class is exposed as file based Stream, Simultaneous read and write operations are supported , Asynchronous read and write operations are also supported . Namespace ：System.IO

Declaration method

FileStream stream = File.Open(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
FileStream stream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);

Parameter description

• filePath Provide the path of the file to be read

• FileMode Enumeration defines various ways to open a file

  • Append： Open an existing file , And place the cursor at the end of the file . If the file doesn't exist , Create file ;

  • Create： Create a new file . If the file already exists , Then delete the old file , Then create a new file ;

  • CreateNew： Specifies that the operating system should create a new file , If the file already exists , Throw an exception ;

  • Open： Open an existing file , If the file doesn't exist , Throw an exception ;

  • OpenOrCreate： Specifies that the operating system should open an existing file , If the file doesn't exist , Create a new file with the specified name to open ;

  • Truncate： Open an existing file , Once the file is opened , Will be truncated to zero byte size . Then we can write new data to the file , But keep the original creation date of the file . If the file doesn't exist , Throw an exception .

• FileAccess Enumeration defines various access rights

  • Read： Gain read access to the file , Then you can read data from the file （ read-only ）.

  • ReadWrite： Get read 、 Write access to the file , Then you can read from the file 、 Write data （ Can read but write ）.

  • Write： Get write access to the file , Data can then be written to a file （ Just write ）.

• FileShare Enumeration defines the types of access to the same file

  • Inheritable： Allow file handles to be inherited by child processes .

  • None： Decline to share current file . Before closing the file , Any request to open the file （ Requests from this process or another process ） Will fail .

  • Read： Allow subsequent open file reads . If this flag is not specified , Before closing the file , Any request to open the file for reading will fail . however , Even if this flag is specified , Additional permissions may still be required to access the file .

  • ReadWrite： Allow subsequent open file read or write . If this flag is not specified , Before closing the file , Any request to open the file for reading or writing will fail . however , Even if this flag is specified , Additional permissions may still be required to access the file .

  • Write： Allow subsequent open file writes . If this flag is not specified , Before closing the file , Any request to open the file for writing will fail . however , Even if this flag is specified , Additional permissions may still be required to access the file .

  • Delete： Allow subsequent deletion of files .

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StreamReader class ： Read file stream

stay C# In language ,StreamReader Class is used to read a string from a stream . It is inherited from TextReader class .

Constructors

StreamReader There are many ways to construct classes , There are four common construction methods ：

Construction method	explain
StreamReader(Stream stream)	Creates a for the specified stream StreamReader Class
StreamReader(string path)	Create a file for the specified path StreamReader Class
StreamReader(Stream stream,Encoding encoding)	Initializes the specified stream with the specified character encoding StreamReader Class
StreamReader(String path, Encoding encoding)	Initializes the specified file with the specified character encoding StreamReader Class

Encoding Coding format commonly used in

1. Default： Current operating system ANSI Code page encoding
2. Unicode： Use Little-Endian Byte order UTF-16 Encoding of format
3. UTF-8：UTF-8 code

Member attribute 、 Member functions

StreamReader The properties and methods commonly used in the class are as follows ：

Properties or methods	effect
Encoding CurrentEncoding	Read-only property , Gets the encoding method used in the current stream
bool EndOfSteam	Read-only property , Gets whether the current stream position is at the end of the stream
void Close()	Closed flow
int Peek()	Gets the integer of the next character in the stream , If no characters are obtained , Then return to -1.
int Read()	Gets the integer of the next character in the stream
int Read(char[] buffer, int index, int count)	Reads the specified maximum number of characters from the current stream into the buffer starting at the specified index position
string ReadLine()	Reads a line of characters from the current stream and returns the data as a string
string ReadToEnd()	Read all characters from the current position of the stream to the result

Code instance

Get the file stream first , In constructing through file stream StreamReader To read the file stream , It can also be constructed directly through the path StreamReader To read the file stream （ Refer to the following write file stream method ）.

class Program
{
    
    static void Main(string[] args)
    {
    
    	// File path 
    	string filePath = Application.dataPath + "/Data/task.csv";
        // Open and get the file stream according to the file path , And get the encoding format of the file stream 
        FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);
        
        // Use the corresponding character encoding format of the file stream to read the file stream 
        StreamReader streamReader = new StreamReader(fileStream);

        // Record one line of records read at a time 
        string strLine;
        // Read line by line CSV Data in 
        while ((strLine = streamReader.ReadLine()) != null)
        {
    
        	// Operate on data 
        	Console.WriteLine(strLine);
        }
        streamReader.Close();
    }
}

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StreamWriter class ： write file

stay C# In language ,StreamWriter Class is used to write a string to a stream .

Constructors

StreamWriter There are many ways to construct classes , There are four common construction methods ：

Construction method	explain
StreamWriter(Stream stream)	Creates a for the specified stream StreamWriter Class
StreamWriter(string path)	Create a file for the specified path StreamWriter Class
StreamWriter(Stream stream,Encoding encoding)	Initializes the specified stream with the specified character encoding StreamWriter Class
StreamWriter(String path, Encoding encoding)	Initializes the specified file with the specified character encoding StreamWriter Class

Member attribute 、 Member functions

StreamWriter The properties and methods commonly used in the class are as follows ：

Properties or methods	effect
bool AutoFlush	attribute , Gets or sets whether the buffer is automatically flushed
Encoding Encoding	Read-only property , Gets the encoding method used in the current stream
void Close()	Closed flow
void Flush()	Refresh buffer
int Write(char value)	Write characters to the stream
void WriteLine(char value)	Writes a character wrap to the stream
Task WriteAsync(char value)	Write characters asynchronously to the stream
Task WriteLineAsync(char value)	Writes characters asynchronously to the stream

Code instance

Construct directly through a path StreamWriter To read the file stream , You can also get the file stream first , In constructing through file stream StreamReader To read the file stream （ Refer to the above reading file stream mode ）.

public void WriteCsv(string strs, string path)
    {
    
        if (!File.Exists(path))
        {
    
            File.Create(path).Dispose();
        }
        else
        {
    
            File.Delete(path);
            File.Create(path).Dispose();
        }
        string mystr;
        //UTF-8 Way, ,true Indicates the additional write mode , Change to false Is to write directly 
        using (StreamWriter stream = new StreamWriter(path, true, Encoding.UTF8))
        {
    
            for (int i = 0; i < Data.SolList.Count; i++)
            {
    
                mystr = "";
                Solution sol = Data.SolList[i];
                //mystr Save a row of data , Use between elements of different columns  ","  separate 
                mystr = sol.SolutionID.ToString() + "," + sol.MakeSpan.ToString() + "," + sol.WaitTime.ToString() + "," + sol.Balance.ToString() + "," + sol.Category;
                stream.WriteLine(mystr);
            }
        }
    }