Open existing file append a single line

Question

I want to open a text file  append a single line to it  then close it

User · Accepted Answer

You can use File AppendAllText for that   File AppendAllText   c  path file txt    text content    Environment NewLine

User · Answer

The technically best way is probably this here    private static async Task AppendLineToFileAsync  NotNull  string path  string line        if  string IsNullOrWhiteSpace path            throw new ArgumentOutOfRangeException nameof path   path   Was null or whitepsace          if   File Exists path            throw new FileNotFoundException  File not found    nameof path         using  var file   File Open path  FileMode Append  FileAccess Write       using  var writer   new StreamWriter file                 await writer WriteLineAsync line           await writer FlushAsync

User · Answer

Might want to check out the TextWriter class         Open File TextWriter tw   new StreamWriter  file txt       Write to file tw WriteLine  test info       Close File tw Close

User · Answer

using  StreamWriter w   File AppendText  myFile txt        w WriteLine  hello

User · Answer

File AppendText will do it   using  StreamWriter w   File AppendText  textFile txt           w WriteLine   -------HURRAY----------        w Flush

User · Answer

We can use   public StreamWriter string path  bool append     while opening the file  string path  C   MyFolder  Notes txt  StreamWriter writer   new StreamWriter path  true     First parameter is a string to hold a full file path Second parameter is Append Mode  that in this case is made true  Writing to the file can be done with   writer Write string   or   writer WriteLine string   Sample Code  private void WriteAndAppend                 string Path   Application StartupPath      notes txt               FileInfo fi   new FileInfo Path               StreamWriter SW              StreamReader SR              if  fi Exists                                SR   new StreamReader Path                   string Line                       while   SR EndOfStream     Till the last line                                       Line   SR ReadLine                                      SR Close                    int x   0                  if  Line Trim   Length  lt   0                                        x   0                                    else                                       x   Convert ToInt32 Line Substring 0  Line IndexOf                                           x                    SW   new StreamWriter Path  true                   SW WriteLine  -----  string Format   0 dd-MMM-yyyy hh mm ss tt    DateTime Now                    SW WriteLine x ToString           textBox1 Text                              else                               SW   new StreamWriter Path                   SW WriteLine  -----    string Format   0 dd-MMM-yyyy hh mm ss tt    DateTime Now                    SW WriteLine  1     textBox1 Text                             SW Flush                SW Close

User · Answer

Choice one  But the first is very simple  The last maybe util for file manipulation     Method 1  I like this  File AppendAllLines       FileAppendAllLines txt        new string      line1    line2    line3         Method 2 File AppendAllText       FileAppendAllText txt        line1    Environment NewLine        line2    Environment NewLine        line3    Environment NewLine      Method 3 using  StreamWriter stream   File AppendText  FileAppendText txt          stream WriteLine  line1        stream WriteLine  line2        stream WriteLine  line3         Method 4 using  StreamWriter stream   new StreamWriter  StreamWriter txt   true         stream WriteLine  line1        stream WriteLine  line2        stream WriteLine  line3         Method 5 using  StreamWriter stream   new FileInfo  FileInfo txt   AppendText          stream WriteLine  line1        stream WriteLine  line2        stream WriteLine  line3

User · Answer

Or you could use File AppendAllLines string  IEnumerable lt string gt    File AppendAllLines   C  Path file txt   new      my text content

User · Answer

display sample reg form in notepad txt using  StreamWriter stream   new FileInfo  D   tt txt   AppendText     ur file location   AppendText         stream WriteLine  Name      textBox1 Text    display textbox data in notepad    stream WriteLine  DOB       dateTimePicker1 Text    display datepicker data in notepad    stream WriteLine  DEP     comboBox1 SelectedItem ToString        stream WriteLine  EXM      listBox1 SelectedItem ToString

[c#] Open existing file, append a single line

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