c# - passing parameter to dowork? -

i calling zip_threading class in class. string = zip_threading(?,?)but problem how can pass parameter values when calling class : string [] files, bool isoriginal. have used in class background worker threading, real problem passing value class , return value when processing finished in make_zip_file class.

public class zip_threading {      public string[] files { get; set; } // recieved zip method zip file names.     public int number;     public string return_path;     public bool isoriginal { get; set; }  // recieved zip method boolean true or fales     public static backgroundworker bgw1 = new backgroundworker(); // make background worker object. public void bgw1_runworkercompleted(object sender, runworkercompletedeventargs e)     {          make_zip_file mzf1 = e.result make_zip_file;         return_path = mzf1.return_path;      }     public make_zip_file bgw_dowork(string[] files, bool isoriginal, make_zip_file argumentest)     {          thread.sleep(100);         argumentest.return_path = argumentest.makezipfile(files,isoriginal);         return argumentest;      }     public void run_async(string []files,bool isoriginal)     {          make_zip_file mzf2 = new make_zip_file();        // mzf2.files = files;         //mzf2.isoriginal = isoriginal;          bgw1.dowork += (sender, e) => e.result = bgw_dowork(files, isoriginal, mzf2);         bgw1.runworkerasync();  }  public  class make_zip_file     {         public string return_path ;         //public string[] files{get;set;}        // public bool isoriginal{get;set;}           public string makezipfile(string[] files, bool isoriginal)         {              string[] filenames = new string[files.length];             if (isoriginal)                 (int = 0; < files.length; i++)                     ***filenames[i] = httpcontext.current.request.physicalapplicationpath + files[i].remove(0, 10).tostring();***             else                 (int = 0; < files.length; i++)                     ***filenames[i] = httpcontext.current.request.physicalapplicationpath + files[i].replace(httpcontext.current.request.urlreferrer.tostring(), "");***             string directoryname = filenames[0].remove(filenames[0].lastindexof('/'));             directoryname = directoryname.substring(directoryname.lastindexof('/') + 1).replace("\\", "");              try             {                  string newfile = httpcontext.current.request.physicalapplicationpath + "images\\thumbnails\\zipfiles\\" + directoryname + ".zip";                 if (file.exists(newfile))                     file.delete(newfile);                 using (zipfile zip = new zipfile())                 {                      foreach (string file in filenames)                     {                          string newfilename = file.replace("\\'", "'");                         zip.compressionlevel = 0;                         zip.addfile(newfilename, "");                     }                      zip.save(newfile);                 }              }             catch (exception ex)             {                 console.writeline("exception during processing {0}", ex);                  // no need rethrow exception our purposes handled.             }              return_path = "images/thumbnails/zipfiles/" + directoryname + ".zip"; return return_path; }} 

now calling method in other class: this

string path=zipa.run_async(filecollection, isoriginal); 

i error in make_zip_file, , mark : object reference not set instance of object* filenames[i] = httpcontext.current.request.physicalapplicationpath + files[i].remove(0, 10).tostring();*

you can use lambda functions nicer syntax. when registering handler dowork, can create lambda calls function , assigns result result property:

make_zip_file mzf2 = new make_zip_file();  bg.dowork += (sender, e) =>      e.result = dowork(files, isoriginal, mzf2); bgw1.runworkerasync(); 

then, dowork method computation , isn't tightly coupled internals of backgroundworker type:

public make_zip_file dowork    (string[] files, bool isoriginal, make_zip_file argumentest) {       thread.sleep(100);       argumentest.return_path = argumentest.makezipfile(files, isoriginal);       return argumentest; }