Read, write and delete files in windows

Sooner or later you'll need to access files from the Window's file system. You'll need to check if a file exists, delete it, move it , you'll need to read and write to it and upload data from it to an iSeries table etc.

To illustrate how easy this is, I've included a full C# project.

This program cleans up a desktop. It moves unwanted items automatically to a 'clean up' folder automatically. Items you don't want to remove are maintained in a text file manually. This file is in 'CleanUp' on your desktop after you run it the first time.
Set it up to run in 'scheduled tasks' to run daily. My desktop gets absolutely splattered with downloads, images, files etc. etc. Now it gets cleaned automatically and the stuff I want to keep is always there. Files are moved but not folders.

The app demonstrates two things.

1. How to access the windows file system
2. How to write a RPG-like app in C#. i.e. in a procedural way There is a 'main', an init etc. There are no class objects created, everything runs from the class. Methods are just like subroutines. Variables are defined that are needed throughout the application as public at the top of the class. (If you define a variable in a method - it is only available within that method.)

using System;
using System.Collections.Generic;

using System.Text;
using System.IO;

using System.Security.Principal;


//Lists each object on the desktop
//Checks if the object is in the list.
//If not, moves it to cleanup.

namespace ClearDesktop
{
    class Program
    {
    
  // Declare class level variables that are accessible from all methods
        public static string cleanUpFolder = @"Cleanup\";
        public static string desktopPathAllUsers = @"C:\Documents and Settings\All Users\Desktop\";
        public static string desktopPath = "";
        public static string cleanUpPath = "";
        public static string cleanUpFile = "";
        public static string allowedOnDesktop = "";
    
     
     
  // Main Routine  
        static void Main(string[] args)
        {
            initializationRoutine();  // Set paths needed
    
            RemoveFilesFromDesktop(desktopPath); // remove unwanted files
            RemoveFilesFromDesktop(desktopPathAllUsers); // some file paths are in 'all users'
        //    Console.ReadLine();
        }




    public static void RemoveFilesFromDesktop(string dir)
        {
// First create directory object from the desktop path
        DirectoryInfo mainDir = new DirectoryInfo(dir);

// This single line fills an array called 'items' of everything on the desktop

// The items in the array are not strings but FileSystemInfo objects.


// What's cool here is each item has a ton of methods and properties


// available directly from it.

            FileSystemInfo[] items = mainDir.GetFileSystemInfos();

// Now go through each item in the array and check if it is allowed
            foreach (FileSystemInfo item in items)
            {
                // Check if the file on the desktop is in the 'allowed' file
                bool allowedyn =  allowedOnDesktop.Contains(item.Name.ToString());
             
                if (item is FileInfo && !allowedyn)
                {
                   // If it is to be moved any existing same name file has to be deleted
                    String alreadyExists = cleanUpPath + item;

                    if (File.Exists(alreadyExists))
                    {
                        try
                        {
                            // Delete the file with the same name
                            File.Delete(alreadyExists);
                        }
                        catch (Exception)
                        {
                         
                         
                        }
                     
                    }

                    // Move the file on the desktop to the clean up folder
                    ((FileInfo)item).MoveTo(cleanUpPath + item);
             
                }
          
            }
        }
    

         
   
        // Get a list of all the files allowed on the desktop
          public static string WhatsAllowedOnTheDesktop(string logFileName)
        {
         
            string contents = "";

            using (FileStream fileStream = new FileStream(logFileName,
                        FileMode.Open,
                        FileAccess.Read,
                        FileShare.None))
            {
                using (StreamReader Reader = new StreamReader(fileStream))
                {
                    contents = Reader.ReadToEnd(); // Reads the entire file in one statement
                    Reader.Close();
                    fileStream.Close();
                }
             
            
            }
            return contents;
        }

        // Write to the 'Allowed files' directory those files you don't want to move
          public static void WriteToLog(string logFileName, string data)
          {
              using (FileStream fileStream = new FileStream(logFileName,
                      FileMode.Append,
                      FileAccess.Write,
                      FileShare.None))
              {
                  using (StreamWriter streamWriter = new StreamWriter(fileStream))
                  {
                      streamWriter.WriteLine(data);
                  }
              }
          }

        // Do basic setup - path names etc.
        public static void initializationRoutine() {
              string username = getUserName();
          
            desktopPath = @"C:\Documents and Settings\" + username + @"\Desktop\";
            cleanUpPath  = desktopPath + cleanUpFolder;
            cleanUpFile = cleanUpPath + @"CleanUpFile.txt";

            //  If the cleanup directory does not exist, create it
            if (!Directory.Exists(cleanUpPath))
            {
                Directory.CreateDirectory(cleanUpPath);
            }

            // Create the log file of items you want to keep on the desktop
         
            if (!File.Exists(cleanUpFile))
            {
                File.Create(cleanUpFile);
            }
         
            allowedOnDesktop = WhatsAllowedOnTheDesktop(cleanUpFile);
            }

        // Get the log on name of the user who started the app in order
        // to know the path of their desktop
        public static string getUserName()
        {
            WindowsIdentity ident = WindowsIdentity.GetCurrent();

            string userid = ident.Name;
            string username = "";
            int pos = userid.IndexOf("\\");
            if (pos > -1)
            {

                username = userid.Substring(pos + 1);
            }
            else
            {
                username = userid;
            }


            return username;

        }

    }



}