Streamwriter is cutting off my last couple of lines sometimes in the middle of a line?

问题

Here is my code. :

FileStream fileStreamRead = new FileStream(pathAndFileName, FileMode.OpenOrCreate, FileAccess.Read, FileShare.None);
FileStream fileStreamWrite = new FileStream(reProcessedFile, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);

                StreamWriter sw = new StreamWriter(fileStreamWrite);

                int readIndex = 0;
                using (StreamReader sr = new StreamReader(fileStreamRead))
                {
                    while (!sr.EndOfStream) {
                        Console.WriteLine("eof" + sr.EndOfStream);
                        readIndex++;
                        Console.WriteLine(readIndex);
                        string currentRecord = "";
                        currentRecord = sr.ReadLine();
                        if (currentRecord.Trim() != "")
                        {
                            Console.WriteLine("Writing " + readIndex);
                            sw.WriteLine(currentRecord);
                        }
                        else {
                            Console.WriteLine("*******************************************spaces ***********************");
                        }
                    }

It is cutting off 2 lines with one test file and half a line, and then 1 line and half a line with the other test file I am running it against.

I am not a streamreader/writer expert you can probably see.

Any ideas or suggestions would be greatly appreciated as this is driving me batty. I am sure it is me using these incorrectly.

回答1:

You are missing Flush/Close or simply using for your writer.

using(FileStream fileStreamWrite = 
  new FileStream(reProcessedFile, FileMode.OpenOrCreate, FileAccess.Write, FileShare.None);
{
  using(StreamWriter sw = new StreamWriter(fileStreamWrite))
  {
   // .... write everything here
  }
}

回答2:

Right after the closing brace of the using statement, do this:

sw.Flush();
sw.Close();

There, that should do it.

回答3:

You need to Flush your StreamWriter. A StreamWriter has a buffer, and it writes to disk only when the buffer is full. By flushing at the end you make sure all the text in the buffer is written to the disk.

回答4:

In addition to other answers (use using, and/or flush/close), would say that they do not actually respond to the question: "why it may cut several lines."

I have an idea on subject that it is related to a fact that you use StreamReader and call EndOfStream twice: in a while loop header, and another inside it.

The only possible way of understanding if the stream ends is try to read some data from it. So I suspect EnfOfStream does it, and reading it twice, may create a problem in stream processing.

To resolve an issue:

Or use simple TextReader, considering that you are reading text file (seems to me)
Or change your logic to call only once, so no more call to Console.WriteLine("eof" + sr.EndOfStream);
Or change your logic, so do not use EndOFStream at all, but read line by line till the line is null.

回答5:

You're not using StreamWriter properly. Also, since you're always reading lines, I would use a method that already does all that for you (and manages it properly).

using (var writer = new StreamWriter("path"))
{
   foreach(var line in File.ReadLines("path"))
   {
       if (string.IsNullOrWhiteSpace(line)) 
       { /**/ }
       else
       { /**/ }
   }
}

... or ...

/* do not call .ToArray or something that will evaluate this _here_, let WriteAllLines do that */
var lines = File.ReadLines("path")
                .Select(line => string.IsNullOrWhiteSpace(line) ? Stars : line);

var encoding = Encoding.ASCII; // whatever is appropriate for you.
File.WriteAllLines("path", lines, encoding);

来源：https://stackoverflow.com/questions/12735897/streamwriter-is-cutting-off-my-last-couple-of-lines-sometimes-in-the-middle-of-a

标签

streamwriter