Append lines to a file using a StreamWriter

Question

I want to append lines to my file  I am using a StreamWriter   StreamWriter file2   new StreamWriter   c  file txt    file2 WriteLine someString   file2 Close      The output of my file should be several strings below each other  but I have only one row  which is overwritten every time I run this code   Is there some way to let the StreamWriter append to an existing file

User · Answer

Replace this line   StreamWriter sw   new StreamWriter  c  file txt      with this code   StreamWriter sw   File AppendText  c  file txt      and then write your line to the text file like this   sw WriteLine  text content

User · Answer

I assume you are executing all of the above code each time you write something to the file  Each time the stream for the file is opened  its seek pointer is positioned at the beginning so all writes end up overwriting what was there before   You can solve the problem in two ways  either with the convenient   file2   new StreamWriter  c  file txt   true     or by explicitly repositioning the stream pointer yourself   file2   new StreamWriter  c  file txt    file2 BaseStream Seek 0  SeekOrigin End

User · Answer

Use this StreamWriter constructor with 2nd parameter - true

User · Answer

You can use like this  using  System IO StreamWriter file  new System IO StreamWriter FilePath true                                                                         file Write  quot SOme Text TO Write quot    Environment NewLine

User · Answer

One more simple way is using the File AppendText it appends UTF-8 encoded text to an existing file  or to a new file if the specified file does not exist and returns a System IO StreamWriter  using  System IO StreamWriter sw   System IO File AppendText logFilePath    log txt                                                          sw WriteLine  this is a log

User · Answer

Actually only Jon s answer  Sep 5  11 at 9 37  with BaseStream Seek worked for my case  Thanks Jon  I needed to append lines to a zip archived txt file   using  FileStream zipFS   new FileStream   c  Temp SFImport test zip  FileMode OpenOrCreate         using  ZipArchive arch   new ZipArchive zipFS ZipArchiveMode Update                 ZipArchiveEntry entry   arch GetEntry  testfile txt            if  entry    null                        entry   arch CreateEntry  testfile txt                      using  StreamWriter sw   new StreamWriter entry Open                           sw BaseStream Seek 0 SeekOrigin End               sw WriteLine  text content

User · Answer

Another option is using System IO File AppendText  This is equivalent to the StreamWriter overloads others have given   Also File AppendAllText may give a slightly easier interface without having to worry about opening and closing the stream  Though you may need to then worry about putting in your own linebreaks

User · Answer

Replace this    StreamWriter file2   new StreamWriter  c  file txt      with this   StreamWriter file2   new StreamWriter  c  file txt   true     true indicates that it appends text

User · Answer

Try this   StreamWriter file2   new StreamWriter   c  file txt   true   file2 WriteLine someString   file2 Close

User · Answer

Use this instead   new StreamWriter  c   file txt   true     With this overload of the StreamWriter constructor you choose if you append the file  or overwrite it    C  4 and above offers the following syntax  which some find more readable   new StreamWriter  c   file txt   append  true

User · Answer

using  FileStream fs   new FileStream fileName FileMode Append  FileAccess Write    using  StreamWriter sw   new StreamWriter fs          sw WriteLine something

[c#] Append lines to a file using a StreamWriter

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