c# - MD5 each file in a folder and also MD5 the folder -

if please ask assistance problem have, i'd open folder display each file , hash , @ end of displayed files i'd hash display of total folder structure. code below isn't correct adds path md5 file md5.

the code below displays each file in listbox , under hash hash code hash folder repeated each file.

private void btnfolder_click(object sender, eventargs e)     {         dialogresult result = folderbrowserdialog1.showdialog();         if (result == dialogresult.ok)         {             _path = folderbrowserdialog1.selectedpath;             txtfolder.text = _path;             // assuming want include nested folders             var files = directory.getfiles(_path, "*.*", searchoption.topdirectoryonly)                                  .orderby(p => p).tolist();             foreach (string items in files)             {                 md5 md5 = md5.create();                 (int = 0; < files.count; i++)                 {                     string file = files[i];                     // hash path                     string relativepath = file.substring(_path.length + 1);                     byte[] pathbytes = encoding.utf8.getbytes(relativepath.tolower());                     md5.transformblock(pathbytes, 0, pathbytes.length, pathbytes, 0);                      // hash contents                     byte[] contentbytes = file.readallbytes(file);                     if (i == files.count - 1)                         md5.transformfinalblock(contentbytes, 0, contentbytes.length);                     else                         md5.transformblock(contentbytes, 0, contentbytes.length, contentbytes, 0);                 }                 lstbox.items.add(items);                 lstbox.items.add(bitconverter.tostring(md5.hash).replace("-", "").tolower());             }         }         else         {             return;         }     } 

thanks in advance assistance.

below code output desired output , requirements.
please read "note" sections in code more information.

you should not run in ui thread since lock down until files have been processed. please @ refactoring method can called in thread.

private void btnfolder_click(object sender, eventargs e) {   dialogresult result = folderbrowserdialog1.showdialog();   if (result == dialogresult.ok)   {     _path = folderbrowserdialog1.selectedpath;     txtinput.text = _path;     // assuming want include nested folders     var files = directory.getfiles(_path, "*.*", searchoption.topdirectoryonly)                           .orderby(p => p).tolist();      md5 totalmd5 = md5.create();     int bytestoreadatonce = 2048; // note: can changed bigger or smaller.      foreach (string singlefile in files)     {       md5 singlemd5 = md5.create();        // hash contents       // note: nice small files, memory eater big files       //byte[] contentbytes = file.readallbytes(singlefile);       //singlemd5.transformfinalblock(contentbytes, 0, contentbytes.length);        using (filestream inputfile = file.openread(singlefile))       {         byte[] content = new byte[bytestoreadatonce];         int bytesread = 0;         // read file in chunks, allowing minimal memory usage.         while ((bytesread = inputfile.read(content, 0, bytestoreadatonce)) > 0)         {           totalmd5.transformblock(content, 0, bytesread, content, 0);           singlemd5.transformblock(content, 0, bytesread, content, 0);         }          // close singlemd5 block 0 length         singlemd5.transformfinalblock(content, 0, 0);          // output per file         lstbox.items.add(string.format("file: {0}", singlefile));         lstbox.items.add(string.format("md5 : {0}", bitconverter.tostring(singlemd5.hash).replace("-", "").toupper()));       }     }      // close totalmd5 empty byte[] , 0 length (basically nothing close block)     totalmd5.transformfinalblock(new byte[0], 0, 0);      // output total     lstbox.items.insert(0, environment.newline);     lstbox.items.insert(0, string.format("total md5 : {0}", bitconverter.tostring(totalmd5.hash).replace("-", "").toupper()));     lstbox.items.insert(0, string.format("root path : {0}", _path));   }   else   {     return;   } } 

with change read each file in chunks, accidentally let code run on folder 287k files in it, totalling ~41gb size.
memory usage didn't go above 7mb during entire processing of directory.