File Class

Summary

Provides static methods for the creation, copying, deletion, moving, and opening of files, and aids in the creation of Stream objects.

Type Definition

Members

• public static void AppendAllLines(string path, IEnumerable<string> contents)
  Appends lines to a file, and then closes the file. If the specified file does not exist, this method creates a file, writes the specified contents to the file, and then closes the file.
  Parameters

  • path: The file to append to. Each line corresponds to a string in the collection.
  • contents: The string collection, each element of which is a line to be written to the file.
• public static void AppendAllText(string path, string contents)
  Appends a string to the end of this file. If the file doesn't exist, created, or overwritten, depending on the value of the overwrite parameter.
  Parameters

  • path: The file to append to.
  • contents: The string to append.
• public static void Copy(string sourceFileName, string destinationFileName)
  Copies an existing file to a new location and optionally overwrites an existing file.
  Parameters

  • sourceFileName: The path to the file to be copied.
  • destinationFileName: The path to the new location, which may be a file name.
• public static void Delete(string path)
  Deletes the specified file.
  Parameters

  • path: The name of the file to be deleted. Wildcard characters are not permitted.
• public static bool Exists(string path)
  Determines whether a file exists.
  Parameters

  • path: The file to check.
  Return Value

  bool: true if the caller has the required permissions and path contains a file; otherwise, false. This method also returns false if path is null, an invalid path, or a zero-length string. If the caller does not have sufficient storage to read the file, no exception is thrown and the method returns false.

• public static StreamReader OpenText(string path)
  Opens a text file for reading with the default encoding.
  Parameters

  • path: The path to the file to be opened.
  Return Value

  StreamReader: A new StreamReader object for the specified file.

• public static string[] ReadAllLines(string path)
  Reads the entire text file into a string array, and then closes the file.
  Parameters

  • path: The file to read.
  Return Value

  string[]: A string array containing the lines of the file.

• public static string ReadAllText(string path)
  Opens a text file, reads all lines of the file, and then closes the file.
  Parameters

  • path: The file to read.
  Return Value

  string: A string containing all lines of the file.

• public static void WriteAllBytes(string path, byte[] bytes)
  Creates a new file, writes the specified byte array to the file, and then closes the file. If the target file already exists, it is overwritten.
  Parameters

  • path: The file to write to.
  • bytes: The byte array to write to the file.
• public static void WriteAllLines(string path, IEnumerable<string> contents)
  Creates a new file, writes a collection of strings to the file, and then closes the file. If the target file already exists, it is overwritten.
  Parameters

  • path: The file to write to.
  • contents: The string collection to write to the file.
• public static void WriteAllText(string path, string contents)
  Creates a new file, writes the specified string to the file, and then closes the file. If the target file already exists, it is overwritten.
  Parameters

  • path: The file to write to.
  • contents: The string to write to the file.

Example

// Create a file and write some text to it
using System.IO;

public class Example
{
    public static void Main()
    {
        string fileName = "myFile.txt";
        string textContent = "This is the content of the file.";

        // Write all text to the file
        File.WriteAllText(fileName, textContent);

        // Read all text from the file
        string readContent = File.ReadAllText(fileName);
        Console.WriteLine(readContent);

        // Append more text to the file
        File.AppendAllText(fileName, " This is appended text.");

        // Read all lines from the file
        string[] lines = File.ReadAllLines(fileName);
        foreach (string line in lines)
        {
            Console.WriteLine(line);
        }

        // Delete the file
        if (File.Exists(fileName))
        {
            File.Delete(fileName);
        }
    }
}