c# - How windows calculate file dimension? -

i calculate binary size of file function:

 public static int binarysize(string path)         {             filestream fs = new filestream(path, filemode.open);             int hexin;             string ret = "";             (int = 0; (hexin = fs.readbyte()) != -1; i++)             {                 ret += convert.tostring(hexin, 2);              }             fs.close();             return ret.length;         }  

an example of problem when calculate dimension of simple black png image (10x10 pixels)

with function find 640 bits => 80 bytes, windows file dimension 136 byte. why difference of 56 bytes? security, permissions or private information windows attach every file?

convert.tostring(hexin,2) not return 8 characters, trims leading zeroes, if hexin 4, returns 100, not 00000100.

you might want change convert.tostring(hexin,2).padleft(8, '0');. you'd want use stringbuilder instead of string ret variable.

by way, reading file determine size bit wasteful. better use fileinfo class file information.