Csharp/CSharp Tutorial/File Directory Stream/File

Create the FileInfo class from the file selected in the OpenFileDialog

using System;
using System.Windows.Forms;
using System.IO;
class MainClass
{
  public static void Main() 
  {
    OpenFileDialog dlgOpen = new OpenFileDialog();
    if (dlgOpen.ShowDialog() == DialogResult.OK)
    {
      FileInfo fi = new FileInfo(dlgOpen.FileName);
      Console.WriteLine("Filename " + fi.FullName );
      Console.WriteLine(" Created at " + fi.CreationTime );
      Console.WriteLine(" Accessed at " + fi.LastAccessTime );
    }
  }
}

File.Exists

using System;
using System.IO;
static class MainClass
{
    static void Main(string[] args)
    {
        Console.WriteLine(File.Exists("c:\\test.txt"));
    }
}

True

File: GetCreationTime and GetLastAccessTime

using System;
using System.Windows.Forms;
using System.IO;
class MainClass
{
  public static void Main() 
  {
    OpenFileDialog dlgOpen = new OpenFileDialog();
    if (dlgOpen.ShowDialog() == DialogResult.OK)
    {
      string s = dlgOpen.FileName;
      Console.WriteLine("Filename " + s);
      Console.WriteLine(" Created at " + File.GetCreationTime(s));
      Console.WriteLine(" Accessed at " + File.GetLastAccessTime(s));
    }
  }
}

File.ReadAllLines

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
class MainClass
{
    static void Main(string[] args)
    {
        StreamWriter writer = new StreamWriter(@"c:\myfile.txt");
        for (int i = 0; i < 3; i++)
        {
            writer.Write(i.ToString());
        }
        writer.Flush();
        writer.Close();
        foreach (string line in File.ReadAllLines(@"c:\myfile.txt"))
        {
            Console.WriteLine(line);
        }
    }
}

012

File.WriteAllLines

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
class MainClass
{
    static void Main(string[] args)
    {
        string[] lines = new string[10];
        for (int i = 0; i < 10; i++)
        {
            lines[i] = String.Format( "This is line number {0}", i);
        }
        File.WriteAllLines(@"c:\test.txt", lines);
        foreach (string line in File.ReadAllLines(@"c:\test.txt"))
        {
            Console.WriteLine(line);
        }
    }
}

Key Members of the System.IO Namespace

Nonabstract I/O Class Type                   Meaning
BinaryReader
BinaryWriter                                 store and retrieve primitive data types (integers, Booleans, strings, and whatnot) as a binary value.
BufferedStream                               temporary storage for a stream of bytes that may be committed to storage.
Directory
DirectoryInfo                                used to manipulate a directory structure. 
DriveInfo                                    provides information for the drives.
File
FileInfo                                     manipulate files. 
FileStream                                   for random file access.
FileSystemWatcher                            monitor the modification of a given external file.
MemoryStream                                 random access to streamed data stored in memory.
Path                                         performs operations on path information.
StreamWriter
StreamReader                                 store and retrieve textual information to or from a file. 
StringWriter
StringReader                                 underlying storage is a string buffer rather than a physical file.