Welcome! This is a C# conversion and implementation of the pretty cool CVS Splitter application.
Original thread and author is here -- http://www.fxfisherman.com/forums/forex-metatrader/tools-utilities/75-csv-splitter-divide-large-csv-files.html
With direct link to the file - http://www.fxfisherman.com/forums/forex-metatrader/tools-utilities/75-csv-splitter-divide-large-csv-files.html#post727
Full source code is included in VB.NET and I will be converting it to C# and fixing a few typo's, etc. All credit goes to the original author and such.