Stream TextReader to a File

Question

I have a TextReader object.

Now, I want to stream the whole content of the TextReader to a File. I cannot use ReadToEnd() and write all to a file at once, because the content can be of high size.

Can someone give me a sample/tip how to do this in Blocks?

Just use ReadLine() in a loop until it returns *null*. – Hans Passant Jul 12 '14 at 16:30 — Hans Passant, Jul 12 '14 at 16:30

Tony · Accepted Answer · 2014-10-17T13:04:46.073

5

using (var textReader = File.OpenText("input.txt"))
using (var writer = File.CreateText("output.txt"))
{
    do
    {
        string line = textReader.ReadLine();
        writer.WriteLine(line);
    } while (!textReader.EndOfStream);
}

edited Oct 17 '14 at 13:04

answered Jul 12 '14 at 16:42

Tony

86
5

I think a do-while loop would be better here – Yuval Itzchakov Jul 12 '14 at 16:53
Your code is invalid. You shouldn't read a line before the `do`, and the order of the read and the write are mixed – Yuval Itzchakov Jul 12 '14 at 18:03

Rahul · Answer 2 · 2014-07-12T16:49:59.683

Something like this. Loop through the reader until it returns null and do your work. Once done, close it.

String line;

try 
{
  line = txtrdr.ReadLine();       //call ReadLine on reader to read each line
  while (line != null)            //loop through the reader and do the write
  {
   Console.WriteLine(line);
   line = txtrdr.ReadLine();
  }
}

catch(Exception e)
{
  // Do whatever needed
}


finally 
{
  if(txtrdr != null)
   txtrdr.Close();    //close once done
}

Yuval Itzchakov · Answer 3 · 2014-07-12T16:56:57.080

0

Use TextReader.ReadLine:

// assuming stream is your TextReader
using (stream)
using (StreamWriter sw = File.CreateText(@"FileLocation"))
{
   while (!stream.EndOfStream)
   {
        var line = stream.ReadLine();
        sw.WriteLine(line);
    }
}

edited Jul 12 '14 at 16:56

answered Jul 12 '14 at 16:45

Yuval Itzchakov

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Stream TextReader to a File

3 Answers3