Описание тега streamreader
Implements a TextReader that reads characters from a byte stream in a particular encoding.
StreamReader is designed for character input in a particular encoding, whereas the Stream class is designed for byte input and output. StreamReader can be used for reading lines of information from a standard text file.
StreamReader defaults to UTF-8 encoding unless specified otherwise, instead of defaulting to the ANSI code page for the current system. UTF-8 handles Unicode characters correctly and provides consistent results on localized versions of the operating system. If you get the current character encoding using the CurrentEncoding property, the value is not reliable until after the first Read method, since encoding auto detection is not done until the first call to a Read method.
By default, a StreamReader is not thread safe. See TextReader.Synchronized for a thread-safe wrapper.