Demonstrates: (1) converting file size (number of bytes) to string description, e.g., "7.405 Kb" (2) reading a file into an array of type byte (3) writing string data to a filepath (4) returning number of files in given directory matching a given pattern (5) returning total size of those pattern-matched files, in bytes (6) obtaining the director…

MyFiles.cs

using System;
using System.IO;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;
using com.williambryanmiller.strings;
using com.williambryanmiller.testing;

namespace com.williambryanmiller.files {
    class MyFiles {

        /* Note: this class file is also found on GitHub Gist
         * @ https://gist.github.com/kyrathasoft/e0dc96b13679ff452139 */      
        
        public static bool appearsToBePureAsciiFile(string pathToFile) {
            bool test = true;
            string filepath = pathToFile;
            using (StreamReader sr = new StreamReader(filepath)) {
                string text = sr.ReadToEnd();
                if (MyTests.appearsToBePureAscii(text)) {
                    //test remains 'true'
                } else {
                    test = false;
                }
            }
            return test;
        }

        public static string getFilesizeDesc(double sizeInBytes) {            

            const double Terabyte = 1099511627776;
            const double Gigabyte = 1073741824;
            const double Megabyte = 1048576;
            const double Kilobyte = 1024;
            

            if (sizeInBytes < Kilobyte) {
                return ((sizeInBytes).ToString() + " bytes");
            }

            if ((sizeInBytes >= Kilobyte) && sizeInBytes < Megabyte) {
                return (((sizeInBytes / Kilobyte).ToString("N3") + " Kb"));
            }

            if((sizeInBytes >= Megabyte) && sizeInBytes < Gigabyte){
                return (((sizeInBytes/Megabyte).ToString("N3") + " Mb"));
            }

            if ((sizeInBytes >= Gigabyte) && sizeInBytes < Terabyte) {
                return ((sizeInBytes / Gigabyte).ToString("N3") + " Gb");
            }

            if (sizeInBytes >= Terabyte){
                return ((sizeInBytes/Terabyte).ToString("N3") + " Tb");
            }

            return "0 bytes";
           
        }

        public static bool wroteStringToTextFile(string s, string filepath) {
            bool test = false;
            try {
                FileInfo fi = new FileInfo(filepath);
                StreamWriter sw = fi.CreateText();
                sw.Write(s);
                sw.Close();
                sw.Dispose();
                test = true;
            } catch (Exception ex) {
                //you could use either Console.Write() or a message box, depending
                //on whether you're using this method in a Console or WinForms app
            }
            return test;
        }

        public static string readAsciiFileIntoString(string filepath) {
            string p = string.Empty;
            using (StreamReader sr = new StreamReader(filepath)) {
                p = sr.ReadToEnd();
            }
            return p;
        }

        public static byte[] ReadByteArrayFromFile(string fileName) {
            byte[] buff = null;
            FileStream fs = new FileStream(fileName, FileMode.Open, FileAccess.Read);
            BinaryReader br = new BinaryReader(fs);
            long numBytes = new FileInfo(fileName).Length;
            buff = br.ReadBytes((int)numBytes);
            return buff;
        }

        public static long returnTotalBytesOfFilesMatchingPattern(string _directory, string _pattern) {
            long total = 0;
            if (!Directory.Exists(_directory)) { return -1; }
            DirectoryInfo di = new DirectoryInfo(_directory);
            FileInfo[] fi = di.GetFiles(_pattern);
            foreach (FileInfo f in fi) {
                total += f.Length;
            }
            return total;
        }

        public static int returnNumFilesMatchingPattern(string _directory, string _pattern) {

            //finds and returns the number of files in given directory matching the pattern
            //if dir passed as first parameter doesn't exist, return -1

            if (!Directory.Exists(_directory)) { return -1; }
            int cnt = 0;
            DirectoryInfo di = new DirectoryInfo(_directory);
            FileInfo[] fi = di.GetFiles(_pattern);
            foreach (FileInfo f in fi) {
                cnt++;
            }
            return cnt;
        }

        public static string dirOfExecutingAssembly() {
            return System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
        }

        public static bool createdAppSubdirectoryIfItDoesntExist(string subdir) {
            bool test = false;
            string myDir = dirOfExecutingAssembly() + "\\" + subdir + "\\";
            if (!Directory.Exists(myDir)) {
                try {
                    Directory.CreateDirectory(myDir);
                    test = true;
                } catch (Exception ex) {

                }
            }
            return test;
        }

        public static bool serializedToDiskInBinary(string filepath, object o) {

            bool success = true;

            FileStream fStream = new FileStream(filepath, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);
            try {
                BinaryFormatter bFormatter = new BinaryFormatter();
                bFormatter.Serialize(fStream, o);
            } catch (Exception serEx) {
                success = false;
                Console.WriteLine(serEx.Message);
            } finally {
                if (fStream != null) {
                    fStream.Close();
                }
            }
            return success;
        }

        public static object deserializeObjectFromDiskToMemory(string filepath) {
            object myObj = null;

            FileStream fs = new FileStream(filepath, FileMode.Open, FileAccess.Read, FileShare.None);
            try {
                BinaryFormatter bFormatter = new BinaryFormatter();
                myObj = (object)bFormatter.Deserialize(fs);
            } catch (Exception deserEx) {
                Console.WriteLine(deserEx.Message);
            } finally {
                if (fs != null) {
                    fs.Close();
                }
            }

            return myObj;
        }

        public static long returnFileLength(string p) {
            if (!System.IO.File.Exists(p)) {
                return -1;
            } else {
                FileInfo fi = new FileInfo(p);
                return fi.Length;
            }
        }

        
    }

}