How to replace a newline in a large text file in C#

问题

How can I replace some of the NewLine characters inside a large text (*.csv) file (~ 2 GB) ?

I cannot read the whole file with File.ReadAllText because a get a OutOfMemory Error and I cannot use the StreamReader because it strips away all the NewLine characters.

Here's some sample text:

Row1Field1;Row1Field2;Row1Field3(NewLine)
Row2Field1;Row2Fie(NewLine)  *<--- This newline is by mistake and I want to replace it!*
ld2;Row2Field3(NewLine)
Row3Field1;Row3Field2;Row3Field3(NewLine)

回答1:

You should use StreamReader ( even if you said you cant ) and read the file line by line. When you find a wrong new line, just keep that line in memory and wire up with the one coming next ( maybe more ones if more than one wrong line happens at once ) and write back in the output stream. It does not matter if ReadLine remove the line ending. Just use WriteLine to write in the output stream and you have again the newlines in place.

来源：https://stackoverflow.com/questions/20572086/how-to-replace-a-newline-in-a-large-text-file-in-c-sharp