Split large Datafile into multiple file with comlete rows

Hi All,
i want to split large amount data file(5 GB) files in to multiple file( 5 files of 1 GB).
i am using below code:-
string destFileLocation = @"C:\Users\";             int index = 0;             long maxFileSize = 1073741824;             byte[] buffer = new byte[65536];             //int a = buffer.Length;             using (Stream source = File.OpenRead(sourceFileName))             {                 try                 { &nbs ...