确定字符串是否为 C# 中的换行符

Question

I am somehow unable to determine whether a string is newline or not. The string which I use is read from a file written by Ultraedit using DOS Terminators CR/LF. I assume this would equate to "\\r\\n" or Environment.NewLine in C#. However , when I perform a comparison like this it always seem to return false :

if(str==Environment.NewLine)

Anyone with a clue on what's going on here?

Answer 1

How are the lines read? If you're using StreamReader.ReadLine (or something similar), the new line character will not appear in the resulting string - it will be String.Empty or (ie "").

Answer 2

Are you sure that the whole string only contains a NewLine and nothing more or less? Have you already tried str.Contains(Environment.NewLine) ?

Answer 3

The most obvious troubleshooting step would be to check what the value of str actually is. Just view it in the debugger or print it out.

Answer 4

Newline is "\\r\\n", not "/r/n". Maybe there's more than just the newline.... what is the string value in Debug Mode?

You could use the new .NET 4.0 Method: String.IsNullOrWhiteSpace

Answer 5

This is a very valid question.

Here is the answer. I have invented a kludge that takes care of it.

static bool StringIsNewLine(string s)
{
    return (!string.IsNullOrEmpty(s)) &&
        (!string.IsNullOrWhiteSpace(s)) &&
        (((s.Length == 1) && (s[0] == 8203)) || 
        ((s.Length == 2) && (s[0] == 8203) && (s[1] == 8203)));
}

Use it like so:

foreach (var line in linesOfMyFile)
{
  if (StringIsNewLine(line)
  {
    // Ignore reading new lines
    continue;
  }

  // Do the stuff only for non-empty lines
  ...
}