C# - Stream

C# includes following standard IO (Input/Output) classes to read/write from different sources like files, memory, network, isolated storage, etc.

Stream: System.IO.Stream is an abstract class that provides standard methods to transfer bytes (read, write, etc.) to the source. It is like a wrapper class to transfer bytes. Classes that need to read/write bytes from a particular source must implement the Stream class.

The following classes inherit Stream class to provide the functionality to Read/Write bytes from a particular source:

FileStream reads or writes bytes from/to a physical file, whether it is a .txt, .exe, .webp, or any other file. FileStream is derived from the Stream class.

MemoryStream: MemoryStream reads or writes bytes that are stored in memory.

BufferedStream: BufferedStream reads or writes bytes from other Streams to improve certain I/O operations' performance.

NetworkStream: NetworkStream reads or writes bytes from a network socket.

PipeStream: PipeStream reads or writes bytes from different processes.

CryptoStream: CryptoStream is for linking data streams to cryptographic transformations.

The following diagram shows the hierarchy of stream classes:

Stream Readers and Writers

StreamReader: StreamReader is a helper class for reading characters from a Stream by converting bytes into characters using an encoded value. It can be used to read strings (characters) from different Streams like FileStream, MemoryStream, etc.

StreamWriter: StreamWriter is a helper class for writing a string to a Stream by converting characters into bytes. It can be used to write strings to different Streams such as FileStream, MemoryStream, etc.

BinaryReader: BinaryReader is a helper class for reading primitive datatype from bytes.

BinaryWriter: BinaryWriter writes primitive types in binary.

The above image shows that FileStream reads bytes from a physical file, and then StreamReader reads strings by converting those bytes to strings. In the same way, the StreamWriter takes a string and converts it into bytes and writes to the FileStream, and then the FileStream writes the bytes to a physical file. So, the FileStream deals with bytes, where as StreamReader and StreamWriter deals with strings.

Learn how to read/write to the File system in the next section.