C# Using TextWriter

TextWriter creates text output. It is used to implement other file classes in the base class library. You can also use it to implement lower-level file IO logic in your higher-level classes.

Note: It's typically better to use StreamWriter in your C# programs. StreamWriter is simpler and easier to use.

Example. First here we look at the TextWriter class, which we instantiate from the result of the File.CreateText static method in the System.IO namespace. The TextWriter class provides useful methods for writing lines and text to a file.

The TextWriter class is easiest to use reliably when you wrap it in a using statement and a resource acquisition statement. This generates internal logic for handling unmanaged resources like file handles.

C# program that uses TextWriter

using System.IO;

class Program
    static void Main()
	// Create a new TextWriter in the resource acquisition statement.
	using (TextWriter writer = File.CreateText("C:\\perl.txt"))
	    // Write one line.
	    writer.WriteLine("First line");
	    // Write two strings.
	    writer.Write("A ");
	    writer.Write("B ");
	    // Write the default newline.

File created by program
    (Located at C:\perl.txt)

First line

The program uses the using-statement, a way to handle unmanaged file resources. The using-statement has a resource acquisition statement. It specifies a read-only variable that is only available in the enclosed statement list.

In the using statement block, the program uses the WriteLine instance method and the Write instance method on the TextWriter instance we allocated. WriteLine the parameter string to the file and automatically adds a newline sequence.

And: The Write method does not add the newline sequence. It just writes the character data specified.

Tip: If you are writing strings that already have line terminations, use the Write method.

The program also uses the NewLine instance property on the TextWriter class. You can assign or read this property. By default, it will be set to the platform's default newline sequence, which on Windows is "\r\n".


StreamWriter. The StreamWriter class actually inherits from the TextWriter class in the base class library. The TextWriter class is an abstract base class, which means it provides functionality for StreamWriter.

Note: MSDN states that StreamWriter represents writing in a particular encoding.

Using StreamWriter

And: For this reason, unless you have specialized encoding requirements, StreamWriter is more appropriate because it manages the encoding.

Summary. We looked at the TextWriter class and related it to the StreamWriter class by noting that it is used as a base class. The TextWriter class is lower-level than StreamWriter because it does not handle encodings automatically.

But: It is still useful in many cases when you have specific encoding requirements or always want to use ASCII encoding.