C# - StreamReader/StreamWriter - File used by another process -

first off, made sure dispose , close (both reader , writer) properly. method i'm doing i'm using using statement; , before this, manually used dispose , close method provided both writer , reader. both of these methods won't solve problem. secondly, point i'm suspecting, i'm processing lot of files both reading , writing. further, every time run program, program run deeper list of files supposed processed (ie, have 10 files, first time run program process first 2 before throwing error; second time run program process first 5 before throwing error , on). how supposed fix problem/bug? in advance!

edit - code attached

    public static void fileprocessing(string initpath, string targetpath, string startline)     {         string line = null;         string content = null;         string nl = "\r\n";         using (streamreader reader = new streamreader(initpath))         {             while (!reader.readline().contains(startline)) ;              while (!reader.endofstream)             {                 line = reader.readline();                 // ignore empty line.                 if (line.length > 0)                 {                     if (!line.contains("<div"))                         content += line += nl;                     else                         break;                 }             }         }          using (streamwriter writer = new streamwriter(targetpath))         {             writer.write(content.trim());         }     }      /// <summary>     /// create temporary text file correspond calendar department page     /// , return path.     /// </summary>     public static string createfile(string path, string title)     {         string npath = path + title + ".txt";         if (!file.exists(npath))             file.createtext(npath);         return npath;     }      /// <summary>     /// return title of page.     /// </summary>     /// <param name="path"></param>     public static string gettitle(string path)     {         string line;         using (streamreader reader = new streamreader(path))         {             (int = 0; < 31; ++i)             {                 line = reader.readline();                 // ignore empty line.                 if (line.length > 0)                 {                     if (line.contains("<h1>"))                     {                         return line.slice(4, -5);                     }                 }             }             return "null";         }     }       /// <summary>     /// content temp path ,     /// output processed text destination path.     /// </summary>     /// <param name="temppath"></param>     /// <param name="title"></param>     public static void writeprocessedtext(string temppath, string targetpath)     {         string content = null;         using (streamreader reader = new streamreader(temppath))         {             string nl = "\r\n";             string line = null;             while (!reader.endofstream)             {                 line = htmlremoval.striptagsregex(reader.readline()) + nl;                 if (line.contains("&nbsp;"))                     line = line.replace("&nbsp;", " ");                 content += line;             }         }          using (streamwriter writer = new streamwriter(targetpath))         {             writer.write(content.trim());         }     } 

file.createtext(npath) not creates filename on disk opens it. either close in createfile method or change return stream.

public static string createfile(string path, string title) {     string npath = path + title + ".txt";     if (!file.exists(npath))         file.createtext(npath); //<-- file not closed !!!     return npath; }