C# TextReader

TextReader in C#

TextReader class available in .NET is a base class for StreamReader and StringReader classes. The StreamReader is used to read characters from a stream. The StringReader is used to read characters from a string. You must use either a StreamReader or a StringReader to read text. These classes are defined in the System.IO namespace. You must import the System.IO namespace before you can use these classes.

Creating a TextReader

We can pass a text file name in a StreamReader constructor to create an object.

Here is C# code. Make sure you have correct path of your text file.

StreamReader sr = new StreamReader(@"C:\Mahesh\King.txt");

Here is VB.NET code:

Dim sr As New StreamReader("C:\Mahesh\King.txt")

Read Methods

The Read method reads the next character from the input stream and advances the character position by one character. The overloaded Read method also takes two parameters, a starting index and number of characters.

The ReadLine method reads a line of characters from the current stream and returns the data as a string.

The ReadBlock method reads a maximum of count characters from the current stream, and writes the data to buffer, beginning at index.

The ReadToEnd method reads all characters from the current position to the end of the TextReader and returns them as one string.

The Peek method reads the next character without changing the state of the reader or the character source. As the name says peek, it actually peeks and returns the next available character without actually reading it from the input stream.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO; 

namespace TextReaderSample
{

    class Program
    {
        static void Main(string[] args)
        {                     

            using (StreamReader sr = new StreamReader(@"C:\Mahesh\King.txt"))
            {

                String line;
                // Read line by line
                while ((line = sr.ReadLine()) != null)
                {
                    Console.WriteLine(line);                

                }
            }
            Console.ReadKey();
        } 

    }

}

 

Here is VB.NET code:

Imports System.IO 

Module Module1 

    Sub Main() 

        Using sr As New StreamReader("C:\Mahesh\King.txt")|
            Dim line As String

            Do
                line = sr.ReadLine()

                If Not (line Is Nothing) Then
                    Console.WriteLine(line)
                End If
            Loop Until line Is Nothing

        End Using

        Console.ReadKey() 

    End Sub 

End Module

 

Summary

In this article, we discussed how to read a text file using a StreamReader.

Here are some more articles:

Text Reader and Text Writer in C# 

StreamReader and StreamWriter Classes in C#