TextReader

The TextReader class in .NET is a fundamental class for reading character data from a stream. It is used to read text from a variety of input sources, including files, network connections, and in-memory buffers. The TextReader class is part of the System.IO namespace in .NET, and it provides a number of methods for reading text from a stream.

The TextReader class is an abstract class, which means that it cannot be instantiated directly. Instead, it provides a number of concrete subclasses that can be used for specific purposes. These subclasses include:

1. StreamReader: This class is used for reading text from a file. It provides methods for reading text from a file, as well as for detecting the end of the file and closing the file.

2. StringReader: This class is used for reading text from an in-memory buffer. It provides methods for reading text from the buffer, as well as for detecting the end of the buffer.

3. NetworkReader: This class is used for reading text from a network connection. It provides methods for reading text from a network socket, as well as for detecting the end of the connection.

The TextReader class provides a number of methods for reading text from a stream. These methods include:

1. Read: This method is used to read a single character from the stream.

2. ReadAsync: This method is used to read a single character from the stream asynchronously.

3. ReadBlock: This method is used to read a block of characters from the stream.

4. ReadBlockAsync: This method is used to read a block of characters from the stream asynchronously.

5. ReadLine: This method is used to read a line of text from the stream.

6. ReadLineAsync: This method is used to read a line of text from the stream asynchronously.

7. Peek: This method is used to peek at the next character in the stream without actually reading it.

8. Close: This method is used to close the stream and release any resources that it may be holding.

Here is an example of using the TextReader class to read text from a file using the StreamReader class:

using System; using System.IO; class Program { static void Main(string[] args) { // Create a new StreamReader object to read from a file using (StreamReader reader = new StreamReader("input.txt")) { // Read the contents of the file into a string string input = reader.ReadToEnd(); // Display the contents of the file Console.WriteLine(input); } } }

In this example, the StreamReader class is used to read the contents of a file called "input.txt" into a string variable. The using statement is used to ensure that the StreamReader object is properly disposed of when it is no longer needed. The ReadToEnd method is then used to read the entire contents of the file into a string variable, which is then displayed on the console.

Here is another example of using the TextReader class to read text from an in-memory buffer using the StringReader class:

using System; using System.IO; class Program { static void Main(string[] args) { // Create a new StringReader object to read from an in-memory buffer using (StringReader reader = new StringReader("Hello, world!")) { // Read the contents of the buffer into a string string input = reader.ReadToEnd(); // Display the contents of the buffer Console.WriteLine(input); } } }

In this example, the StringReader class is used to create an in-memory buffer containing the string "Hello, world!". The using statement is used to ensure that the StringReader object is properly disposed of when it is no longer needed.