C# - Files and Folders

// Directory of Window Form Application

string appPath = Path.GetDirectoryName(Application.ExecutablePath);

// Directory of Any Loaded Assembly

string path = Path.GetDirectoryName(Assembly.GetAssembly(typeof(MyClass)).CodeBase);

File Stream – Open Files

//Open existing file for read and write

using (var fileStream = new FileStream(@"c:\file.txt", FileMode.Open))

{

   

}

//Open existing file for reading

using (var fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Read))

{

  

}

//Open existing file for writing

using (var fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Write))

{

  

}

//Open file for writing(with seek to end), if the file doesn't exist create it

using (var fileStream = new FileStream(@"c:\file.txt", FileMode.Append))

{

   

}

//Create new file and open it for read and write, if the file exists overwrite it

using (var fileStream = new FileStream(@"c:\file.txt", FileMode.Create))

{

  

}

//Create new file and open it for read and write, if the file exists throw exception

using (var fileStream = new FileStream(@"c:\file.txt", FileMode.CreateNew))

{

   

}

File Stream – Read Text Files

//Read Text File into String

//It's super easy to read whole text file into string using static class File and its method File.ReadAllText.

string text = File.ReadAllText(@"c:\file.txt", Encoding.UTF8);

           

//Read Text File into String(with StreamReader)

string text;

var fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Read);

using (var streamReader = new StreamReader(fileStream, Encoding.UTF8))

{

    text = streamReader.ReadToEnd();

}

File Stream – Load Text from Files To String

//Read Text File into String Array

//Again, the easy way is to use static class File and it's method File.ReadAllLi­nes.

string[] lines = File.ReadAllLines(@"c:\file.txt", Encoding.UTF8);

//Read Text File into String Array(with StreamReader)

string[] lines;

var list = new List<string>();

var fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Read);

using (var streamReader = new StreamReader(fileStream, Encoding.UTF8))

{

    string line;

    while ((line = streamReader.ReadLine()) != null)

    {

        list.Add(line);

    }

}

lines = list.ToArray();

           

//Read Text File Line by Line

foreach (string line in File.ReadLines(@"c:\file.txt", Encoding.UTF8))

{

    // process the line

}

//Read Text File Line by Line(with StreamReader)

var fileStream = new FileStream(@"c:\file.txt", FileMode.Open, FileAccess.Read);

using (var streamReader = new StreamReader(fileStream, Encoding.UTF8))

{

    string line;

    while ((line = streamReader.ReadLine()) != null)

    {

        // process the line

    }

}

//To load text from file to string you can use StreamReader.

string text;

using (var streamReader = new StreamReader(@"c:\file.txt", Encoding.UTF8))

{

    text = streamReader.ReadToEnd();

}

Get File from Directory 

//Get files from directory

//Method Directory.GetFiles returns string array with files names(full paths).

string[] filePaths = Directory.GetFiles(@"c:\MyDir\");

//Get files from directory (with specified extension)

string[] filePaths = Directory.GetFiles(@"c:\MyDir\", "*.bmp");

//Get files from directory(including all subdirectories)

//If you want to search also in subfolders use parameter SearchOption.A­llDirectories.

string[] filePaths = Directory.GetFiles(@"c:\MyDir\", "*.bmp", SearchOption.AllDirectories);

Delete All Files       

//Delete all files

string[] filePaths = Directory.GetFiles(@"c:\MyDir\");

foreach (string filePath in filePaths)

    File.Delete(filePath);

//Delete all files(one - row example)

//To delete all files using one code line, you can use Array.ForEach with combination of anonymous method.

Array.ForEach(Directory.GetFiles(@"c:\MyDir\"),

              delegate (string path) { File.Delete(path); });

//Directory of windows forms application(.exe)

string appPath = Path.GetDirectoryName(Application.ExecutablePath);

//Directory of any loaded assembly(.exe or .dll)

string path = Path.GetDirectoryName(

                     Assembly.GetAssembly(typeof(MyClass)).CodeBase);

File Attributes – How To Get Or Set File Attributes

//Get file attributes

string filePath = @"c:\test.txt";

FileAttributes fileAttributes = File.GetAttributes(filePath);

//Set file attributes

File.SetAttributes(filePath, FileAttributes.Normal);

File.SetAttributes(filePath, FileAttributes.Archive | FileAttributes.ReadOnly);

// check whether a file is read only

bool isReadOnly = ((File.GetAttributes(filePath) & FileAttributes.ReadOnly) == FileAttributes.ReadOnly);

// check whether a file is hidden

bool isHidden = ((File.GetAttributes(filePath) & FileAttributes.Hidden) == FileAttributes.Hidden);

// check whether a file has archive attribute

bool isArchive = ((File.GetAttributes(filePath) & FileAttributes.Archive) == FileAttributes.Archive);

// check whether a file is system file

bool isSystem = ((File.GetAttributes(filePath) & FileAttributes.System) == FileAttributes.System);

//Add file attributes to current ones

File.SetAttributes(filePath, File.GetAttributes(filePath) | FileAttributes.Hidden);

//Set (add) both archive and read only attributes

File.SetAttributes(filePath, File.GetAttributes(filePath) | (FileAttributes.Archive | FileAttributes.ReadOnly));

//Delete/clear file attributes from current ones

File.SetAttributes(filePath, File.GetAttributes(filePath) & ~FileAttributes.Hidden);

//Delete/clear archive and read only attributes

File.SetAttributes(filePath, File.GetAttributes(filePath) & ~(FileAttributes.Archive | FileAttributes.ReadOnly));

File Stream – Read Files

//Read file using FileStream

//First create FileStream to open a file for reading.

//Then call FileStream.Read in a loop until the whole file is read.

//Finally close the stream.

public static byte[] ReadFile(string filePath)

{

    byte[] buffer;

    FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);

    try

    {

        int length = (int)fileStream.Length;  // get file length

        buffer = new byte[length];            // create buffer

        int count;                            // actual number of bytes read

        int sum = 0;                          // total number of bytes read

        // read until Read method returns 0 (end of the stream has been reached)

        while ((count = fileStream.Read(buffer, sum, length - sum)) > 0)

            sum += count;  // sum is a buffer offset for next reading

    }

    finally

    {

        fileStream.Close();

    }

    return buffer;

}