C# 5.0 Programmer's Reference

416 ❘ CHAPTER 18 Streams
The code first creates a MemoryStream. It then creates a BinaryWriter associated with the stream
and uses its Write method to write a string into it.
Next, the code uses the Seek method to rewind the stream to the beginning of the data. It then creates
a BinaryReader associated with the stream, uses its ReadString method to read a string from the
stream, and displays the string in a message box.
The code finishes by disposing of the objects it used. This is a bit more confusing than usual
because the reader and writer are associated with the stream. When the program disposes of the
reader or writer, those objects automatically close their underlying stream. That means you cannot
dispose of the writer before you finish with the reader. If you are careful, you can use a properly
ordered sequence of using statements, but this example seems simpler if you just dispose of the
objects all at once at the end.
BinaryReader and BinaryWriter
The BinaryReader and BinaryWriter classes are helper classes that work with stream classes.
They provide an interface that makes it easier to read and write data in a stream. For example, the
BinaryReader class’s ReadInt32 method reads a 4-byte (32-bit) signed integer from the stream.
Similarly, the ReadUInt16 method reads a 2-byte (16-bit) unsigned integer.
These classes still work at a relatively low level, and you should generally use higher-level classes to
read and write data if possible. For example, you shouldn’t tie yourself to a particular representation
of an integer (32- or 16-bit) unless you must.
Both the BinaryReader and BinaryWriter classes have a BaseStream property that returns a
reference to the underlying stream. Note that their Close and Dispose methods automatically
close their underlying streams.
The following table describes the BinaryReader class’s most useful methods.
Method
Close
PeekChar
Read
ReadBoolean
ReadByte
Purpose
Closes the BinaryReader and its underlying stream.
Reads the stream’s next character but does not advance
the reader’s position.
Reads characters from the stream and advances the reader’s
position.
Reads a bool from the stream and advances the reader’s
position by 1 byte.
Reads a byte from the stream and advances the reader’s
position by 1 byte.
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