.net - C# - Compress byte[] -

i receive zip file base64 string, convert byte[], open in memory, modify content, , 'compress' new byte[] base64 string again.

my problem, don't know how 'compress' new byte[] zip format.

public string modifyzipcontent(string base64) {     zippackage zippackage = null;     memorystream memorystream = null;      long lenght;      byte[] data = convert.frombase64string(base64);     byte[] buffer;     byte[] newdata;      int arrayoffset = 0;      memorystream = new memorystream();     memorystream.write(data, 0, data.length);      zippackage = (zippackage)package.open(memorystream, filemode.open);      packagepartcollection zipparts = zippackage.getparts();      // awful         foreach(zippackagepart zippart in zipparts) {             using(stream stream = zippart.getstream()) {                 arrayoffset += (int)stream.length;             }         }          newdata = new byte[arrayoffset];     // end      arrayoffset = 0;     foreach(zippackagepart zippart in zipparts) {         using(stream stream = zippart.getstream()) {             lenght = stream.length;             buffer = new byte[lenght];              stream.read(buffer, 0, (int)lenght);              buffer.blockcopy(buffer, 0, newdata, arrayoffset, buffer.length);             arrayoffset += buffer.length;         }     }      return convert.tobase64string(newdata); } 

i haven't tested this, along these lines should work...

// requires system.io.compression using statement.  byte[] bytes = new byte[256]; // byte[] here instead of empty one. using (var zipfile = zipfile.open("c:/zipfile.zip", ziparchivemode.update)) {     var entry = zipfile.createentry("yourentrypathhere");     using (var stream = entry.open())     {         stream.write(bytes, 0, bytes.length);     } }