StreamReader Class and StreamWriter Class

Aug 26, 2008
by David Cumps

Part of my 2008 study notes for exam 70-536 (.NET Framework 2.0).

Overview

Provides extra helper methods intended to read a stream as a string.
Calling Close() on a StreamReader will close the underlying Stream as well.

Good practice

Remember to call Close on a stream.
Use using statements when you want the stream to be closed automatically at the end.

Examples

Read a File

// FileStream is simply a stream around a file, overriding Stream methods
FileStream a = new FileStream(@"C:\Public\Test.txt", FileMode.Open);
 
while (a.Position != a.Length)
{
    Console.Write((char)a.ReadByte());
}
 
a.Seek(0, SeekOrigin.Begin);
 
StreamReader b = new StreamReader(a);
Console.WriteLine(b.ReadToEnd());
b.Close();

Writing a File

// FileStream is simply a stream around a file, overriding Stream methods
FileStream a = new FileStream(@"C:\Public\Test.txt", FileMode.Create);
 
using (StreamWriter writer = new StreamWriter(a))
{
    writer.AutoFlush = true;
    writer.WriteLine("Hello World");
}
 
// The FileStream has been closed because of the using statement
a = new FileStream(@"C:\Public\Test.txt", FileMode.Open);
StreamReader b = new StreamReader(a);
Console.WriteLine(b.ReadToEnd());
b.Close();
 
// Simple version if you only need to read the entire file
Console.WriteLine(File.ReadAllText(@"C:\Public\Test.txt"));