Csharp/CSharp Tutorial/File Directory Stream/File Access Mode

Create FileStream from FileInfo with file mode, file access and file sharing

using System;
using System.IO;
public class MainClass
{
  static void Main(string[] args)
  {
    FileInfo MyFiles = new FileInfo(@"c:\Testing.txt");
    FileStream MyFileStream1 = MyFiles.Open(FileMode.Append, FileAccess.Read, FileShare.None);
    int MyBytes = MyFileStream1.ReadByte();
    MyFileStream1.Close();    
  }
}

Creates a file with read-write access that allows others to read

using System;
using System.IO;
public class MainClass
{
  static void Main(string[] args)
  {
    FileStream MyFileStream1 = new FileStream(@"c:\Testing.txt", FileMode.Create);
    
    int MyBytes = MyFileStream1.ReadByte();
    
    MyFileStream1.Close();    
  }
}

FileStream is opened for FileAccess.ReadWrite (default) and FileShare.None (default)

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.IO.rupression;
using System.Net;
using System.Net.Mail;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        using (FileStream fs1 = File.Open("c:\\test.txt", FileMode.Open)){
        }
    }
}

FileStream is opened for FileAccess.ReadWrite FileShare.Read and has had its entire contents truncated (due to FileMode.Truncate)

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.IO.rupression;
using System.Net;
using System.Net.Mail;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        using (FileStream fs3 =File.Open("c:\\test.txt", FileMode.Truncate, FileAccess.ReadWrite, FileShare.Read))
        {
        }
    }
}

FileStream is opened for FileAccess.Write FileShare.None (default) and is positioned at the end (because of FileMode.Append)

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.IO;
using System.IO.rupression;
using System.Net;
using System.Net.Mail;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using System.Text;
public class MainClass
{
    public static void Main()
    {
        using (FileStream fs2 = File.Open("c:\\test.txt", FileMode.Append, FileAccess.Write))
        {
        }
    }
}

Use FileStream with StreamWriter to provide a greater degree of control in how you open the file

using System;
using System.IO;
public class MainClass
{
  static void Main(string[] args)
  {
    FileStream MyFileStream = new FileStream(@"c:\Testing.txt", FileMode.CreateNew, FileAccess.Write, FileShare.None);
    StreamWriter MyStreamWriter = new StreamWriter(MyFileStream);
    MyStreamWriter.Write("a string");
    MyFileStream.Close();
    MyStreamWriter.Close();
    
  }
}