Create a txt file if doesn t exist and if it does append a new line

Question

I would like to create a  txt file and write to it  and if the file already exists I just want to append some more lines   string path     E  AppServ Example txt   if   File Exists path         File Create path       TextWriter tw   new StreamWriter path       tw WriteLine  The very first line         tw Close      else if  File Exists path         TextWriter tw   new StreamWriter path       tw WriteLine  The next line         tw Close         But the first line seems to always get overwritten    how can I avoid writing on the same line  I m using this in a loop    I know it s a pretty simple thing  but I never used the WriteLine method before  I m totally new to C

User · Answer

When you start StreamWriter it s override the text was there before  You can use append property like so   TextWriter t   new StreamWriter path  true

User · Answer

You just want to open the file in  append  mode    http   msdn microsoft com en-us library 3zc0w663 aspx

User · Answer

Use the correct constructor   else if  File Exists path         using var tw   new StreamWriter path  true                 tw WriteLine  The next line

User · Answer

You could use a FileStream  This does all the work for you   http   www csharp-examples net filestream-open-file

User · Answer

else if  File Exists path         using  StreamWriter w   File AppendText path                         w WriteLine  The next line                  w Close

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string path     E  AppServ Example txt   File AppendAllLines path  new       The very first line         See also File AppendAllText     AppendAllLines will add a newline to each line without having to put it there yourself   Both methods will create the file if it doesn t exist so you don t have to    File AppendAllText File AppendAllLines

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string path   E  AppServ Example txt    if  File Exists path        File Create path  Dispose        using  TextWriter tw   new StreamWriter path              tw WriteLine  The very first line                 else if  File Exists path        using TextWriter tw   new StreamWriter path              tw WriteLine  The next line

User · Answer

File AppendAllText adds a string to a file  It also creates a text file if the file does not exist  If you don t need to read content  it s very efficient  The use case is logging   File AppendAllText  C   log txt    hello world n

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You don t actually have to check if the file exists  as StreamWriter will do that for you  If you open it in append-mode  the file will be created if it does not exists  then you will always append and never over write  So your initial check is redundant   TextWriter tw   new StreamWriter path  true   tw WriteLine  The next line     tw Close

User · Answer

You can just use File AppendAllText   Method this will solve your problem  This method will take care of File Creation if not available  opening and closing the file   var outputPath     E  Example txt   var data    Example Data   File AppendAllText outputPath  data

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From microsoft documentation  you can create file if not exist and append to it in a single call File AppendAllText Method  String  String    NET Framework  current version  Other Versions   Opens a file  appends the specified string to the file  and then closes the file  If the file does not exist  this method creates a file  writes the specified string to the file  then closes the file  Namespace    System IO Assembly   mscorlib  in mscorlib dll   Syntax C C  F VB public static void AppendAllText      string path      string contents   Parameters path Type  System String The file to append the specified string to  contents Type  System String The string to append to the file   AppendAllText

User · Answer

Try this   string path     E  AppServ Example txt   if   File Exists path         using  var txtFile   File AppendText path                 txtFile WriteLine  The very first line             else if  File Exists path              using  var txtFile   File AppendText path                 txtFile WriteLine  The next line

User · Answer

using var tw   new StreamWriter path  File Exists path          tw WriteLine message

[c#] Create a .txt file if doesn't exist, and if it does append a new line

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