You can use the StreamReader class for reading, and StreamWriter for writing. Unlike the more generalized FileStream class, StreamReader and StreamWriter are specialized classes for text files containing ASCII or Unicode characters. There are useful methods which make text file access more convenient.
StreamReader has several overloaded constructors but here are the two most useful ones:
public StreamReader (string path)
public StreamReader (string path, Encoding encoding)
If the first constructor is used, StreamReader will try to determine the file's encoding format from the text file itself. 
 It is possible to determine if a text file is encoded using Unicode ...