string strings = "4,6,8\n9,4";
string [] split = strings .Split(new Char [] {',' , '\n' });
EDIT
Try following if you get any unnecessary empty items. String.Split Method (String[], StringSplitOptions)
string [] split = strings .Split(new Char [] {',' , '\n' },
StringSplitOptions.RemoveEmptyEntries);
EDIT2
This works for your updated question. Add all the necessary split characters to the char []
.
string [] split = strings.Split(new Char[] { ',', '\\', '\n' },
StringSplitOptions.RemoveEmptyEntries);