Get the source of folder size in C # implementation

usingSystem;usingSystem.Collections.Generic;usingSystem.IO;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespacefilelist{ Public classProgram { Public Static voidMain (string[] args)            {Console.WriteLine (); LongLength = Getdirectorylength (@"D:\Folder\ Dish four"); Console.WriteLine (length. ToString ("N0"));            Console.WriteLine (); LongLength2 = FileSize (@"D:\Folder\ Dish four"); Console.WriteLine (length2. ToString ("N0"));        Console.WriteLine (DateTime.Now.Millisecond); }         Public Static LongGetdirectorylength (stringDirpath) {            //determines whether a given path exists and exits if it does not exist            if(!directory.exists (dirpath))return 0; LongLen =0; //define a DirectoryInfo objectDirectoryInfo di =NewDirectoryInfo (Dirpath); //get the size of all files in the Di directory through the GetFiles method            foreach(FileInfo fiinchdi. GetFiles ()) {Len+=fi.            Length; }            //get all the folders in Di and coexist in a new object array for recursiondirectoryinfo[] dis =di.            GetDirectories (); if(Dis. Length >0)            {                 for(inti =0; i < Dis. Length; i++) {len+=getdirectorylength (Dis[i].                FullName); }            }            returnLen; }        //It is also the idea of using recursion, only to judge by the exits method of the file class.//whether the corresponding file is in the given path         Public Static LongFileSize (stringFilePath) {            Longtemp =0; //determines whether the current path points to a file            if(File.exists (filePath) = =false)            {                string[] str1 =directory.getfilesystementries (FilePath); foreach(stringS1inchstr1) {Temp+=FileSize (S1); }            }            Else            {                //define a FileInfo object to associate with the file that FilePath points to,//to get its sizeFileInfo FileInfo =NewFileInfo (FilePath); returnfileinfo.length; }            returntemp; }    }}

Get the source of folder size in C # implementation