System IO IOException file used by another process

Question

I ve been working on this small piece of code that seems trivial but still  i cannot really see where is the problem  My functions do a pretty simple thing  Opens a file  copy its contents  replace a string inside and copy it back to the original file  a simple search and replace inside a text file then   I didn t really know how to do that as I m adding lines to the original file  so I just create a copy of the file   file temp  copy also a backup  file temp  then delete the original file file  and copy the file temp to file  I get an exception while doing the delete of the file  Here is the sample code   private static bool modifyFile FileInfo file  string extractedMethod  string modifiedMethod                Boolean result   false          FileStream fs   new FileStream file FullName     tmp   FileMode Create  FileAccess Write           StreamWriter sw   new StreamWriter fs            StreamReader streamreader   file OpenText            String originalPath   file FullName          string input   streamreader ReadToEnd            Console WriteLine  input    0    input            String tempString   input Replace extractedMethod  modifiedMethod           Console WriteLine  replaced String  0    tempString            try                       sw Write tempString               sw Flush                sw Close                sw Dispose                fs Close                fs Dispose                streamreader Close                streamreader Dispose                 File Copy originalPath  originalPath     old   true               FileInfo newFile   new FileInfo originalPath     tmp                File Delete originalPath               File Copy fs   originalPath  true                result   true                    catch  Exception ex                        Console WriteLine ex                      return result           And the related exception  System IO IOException  The process cannot access the file  E  mypath myFile cs  because it is being used by another process     at System IO   Error WinIOError Int32 errorCode  String maybeFullPath     at System IO File Delete String path     at callingMethod modifyFile FileInfo file  String extractedMethod  String modifiedMethod    Normally these errors come from unclosed file streams  but I ve taken care of that  I guess I ve forgotten an important step but cannot figure out where  Thank you very much for your help

User · Answer

Are you running a real-time antivirus scanner by any chance   If so  you could try  temporarily  disabling it to see if that is what is accessing the file you are trying to delete   Chris  suggestion to use Sysinternals process explorer is a good one

User · Answer

It worked for me   Here is my test code   Test run follows   using System  using System Collections Generic  using System IO  using System Linq  using System Text   namespace ConsoleApplication1       class Program               static void Main string   args                        FileInfo f   new FileInfo args 0                bool result   modifyFile f  args 1  args 2                      private static bool modifyFile FileInfo file  string extractedMethod  string modifiedMethod                          Boolean result   false               FileStream fs   new FileStream file FullName     tmp   FileMode Create  FileAccess Write                StreamWriter sw   new StreamWriter fs                StreamReader streamreader   file OpenText                 String originalPath   file FullName               string input   streamreader ReadToEnd                 Console WriteLine  input    0    input                String tempString   input Replace extractedMethod  modifiedMethod                Console WriteLine  replaced String  0    tempString                try                                 sw Write tempString                    sw Flush                     sw Close                     sw Dispose                     fs Close                     fs Dispose                     streamreader Close                     streamreader Dispose                     File Copy originalPath  originalPath     old   true                    FileInfo newFile   new FileInfo originalPath     tmp                     File Delete originalPath                    File Copy originalPath     tmp   originalPath  true                    result   true                              catch  Exception ex                                  Console WriteLine ex                               return result                       C  testarea gt ConsoleApplication1 exe file txt padding testing input            lt style type  text css  gt           lt  --           mytable             border-collapse  collapse            width  300px                       mytable th            mytable td                      border  1px solid  000            padding  3px                       mytable tr highlight             background-color   eee                       -- gt           lt  style gt  replaced String          lt style type  text css  gt           lt  --           mytable             border-collapse  collapse            width  300px                       mytable th            mytable td                      border  1px solid  000            testing  3px                       mytable tr highlight             background-color   eee                       -- gt           lt  style gt

User · Answer

I realize that I is kinda late  but still better late than never  I was having similar problem recently  I used XMLWriter to subsequently update XML file and was receiving the same errors  I found the clean solution for this   The XMLWriter uses underlying FileStream to access the modified file  Problem is that when you call XMLWriter Close   method  the underlying stream doesn t get closed and is locking the file  What you need to do is to instantiate your XMLWriter with settings and specify that you need that underlying stream closed   Example   XMLWriterSettings settings   new Settings    settings CloseOutput   true  XMLWriter writer   new XMLWriter filepath  settings     Hope it helps

User · Answer

The code works as best I can tell   I would fire up Sysinternals process explorer and find out what is holding the file open   It might very well be Visual Studio

User · Answer

Try this  It works in any case  if the file doesn t exists  it will create it and then write to it  And if already exists  no problem it will open and write to it     using  FileStream fs  new FileStream   File txt  FileMode Create FileAccess ReadWrite          fs close        using  StreamWriter sw   new StreamWriter   File txt            sw WriteLine  bla bla bla        sw Close

User · Answer

System Drawing Image FileUploadPhoto   System Drawing Image FromFile location1                                    FileUploadPhoto Save location2                                    FileUploadPhoto Dispose

User · Answer

My reputation being too small to comment an answer  here is my feedback concerning roquen answer  using settings on xmlwriter to force the stream to close   it works perfectly and it made me save a lot of time  roquen s example requires some adjustment  here is the code that works on  NET framework 4 8        XmlWriterSettings settings   new XmlWriterSettings        settings CloseOutput   true      writer   XmlWriter Create stream  settings

User · Answer

After coming across this error and not finding anything on the web that set me right  I thought I d add another reason for getting this Exception - namely that the source and destination paths in the File Copy command are the same  It took me a while to figure it out  but it may help to add code somewhere to throw an exception if source and destination paths are pointing to the same file   Good luck

User · Answer

After creating a file you must force the stream to release the resources     FSm is stream for creating file on a path   System IO FileStream FS   new System IO FileStream path   fname                                                     System IO FileMode Create   pro CopyTo FS   FS Dispose

User · Answer

Sounds like an external process  AV   is locking it  but can t you avoid the problem in the first place   private static bool modifyFile FileInfo file  string extractedMethod  string modifiedMethod        try               string contents   File ReadAllText file FullName           Console WriteLine  input    0    contents           contents   contents Replace extractedMethod  modifiedMethod           Console WriteLine  replaced String  0    contents           File WriteAllText file FullName  contents           return true            catch  Exception ex                Console WriteLine ex ToString             return false

[c#] System.IO.IOException: file used by another process

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