C# Textreader

In the C# programming language, the TextReader is a class that is found in the System.IO namespace. It defines a reader text that provides a way to read text or a sequential series of characters. The TextReader class is part of .NET. It is a base class for the StreamReader and StringReader classes. The C# StreamReader is commonly utilized to read characters from a stream. The C# StringReader is commonly utilized to read characters from a String. However, we can use both classes to read the text.

Syntax:

It has the following syntax.

TextReader reader = new DerivedTextReader ();

In this syntax,

• ✅ TextReader: It is used to represent an abstract base class in the System.IO namespace.
• ✅ reader: It is the variable name that will hold the reference to the TextReader Object.
• ✅ new: It is the keyword that creates an instance of the derived class.
• ✅ DerivedTextReader: It represents the constructor of a class that derives from TextReader.

Simple C# TextReader Example

Let us take an example to illustrate the TextReader in C#.

Example

using System;  

using System.IO;  

namespace TextReaderExample  

{  

    class C# Tutorial  

    {  

        static void Main(string[] args)  

        {  

            using (TextReader tr = File.OpenText("e:\\f.txt"))  

            {

                Console.WriteLine(tr.ReadToEnd());  

            }  

        }  

    }  

}

Output:

Hello C#

C# File Handling by C# Tutorial.

Explanation:

In this example, we are using the TextReader class in C#. First, we use the File.OpenText method to open a text file named f.txt, and the file is located at the specified path (f.txt). After that, we are using the ReadToEnd method to read all the file contents and display the output using the Console.WriteLine method.

C# TextReader Example to Read One Line

Let us take an example to illustrate the TextReader class to read a single line from the file.

Example

using System;

using System.IO;

namespace C# Tutorial

{  

    class Program  

    {  

        static void Main(string[] args)  

        {  

            using (TextReader tr = File.OpenText("e:\\f.txt"))  

            {  

                Console.WriteLine(tr.ReadLine());  

            }  

        }  

    }  

}

Output:

Hello C#

Explanation:

In this example, we use the File.OpenText method to open the file f.txt. The file is located at the given path (e:\\f.txt). Inside the using block, we have used the ReadLine method to read the first line of the file content. In the end, we are using the Console.WriteLine method to print the output.

How to read a file using StreamReader in C#

In C# , the StreamReader class is commonly used to read text files. It provides a method to read data from files line by line. It makes the file handling simple and convenient.

Here, we will discuss how to read a file step by step in C#.

1) Create an Object of FileInfo

If we want to create an object of the FileInfo, we can use the following syntax:

FileInfo file = new FileInfo(@" D:C# Tutorialfile.txt " );

In this syntax,

• ✅ The FileInfo class is used to get information about a file and perform operations like create, open, delete, or move.
• ✅ An object of FileInfo is created for the path D:C# Tutorialfile.txt.

2) Open the File for Reading

We can use the following statement to open the file for reading.

FileStream fs = file.Open(FileMode.OpenOrCreate, FileAccess.Read , FileShare.Read);

In this syntax,

• ✅ FileStream: The FileStream is a class in the System.IO namespace. It is utilized to read or write files.
• ✅ fs: The fs is the object of type Filestream that will store the reference to the opened file stream.
• ✅ Open : The Open method of FileInfo is utilized to open an existing file or create a new file.
• ✅ OpenOrCreate: It is the parameter that defines how we can open or create a file.

3) Create a Stream Reader Object

If we want to create a stream reader object, we can use the following syntax:

StreamReader sr = new StreamReader ( fs );

In this syntax,

• ✅ StreamReader: It is the class that is used to read characters or text.
• ✅ sr: It is an object of the StreamReader class.
• ✅ new: It is the keyword that creates an instance of the StreamReader class.
• ✅ fs: It is an argument that is passed to the StreamReader.

4) Read All Content from the File

If we want to read all the file content, we can utilize the following syntax:

string fileContent = sr.ReadToEnd();

In this syntax,

• ✅ fileContent: The fileContent is a string variable that will store the data read from the file.

5) Close the StreamReader and FileStream

If we want to close the StreamReader and FileStream, we can use the following syntax:

sr.Close();

fs.Close();

In this syntax,

• ✅ Close: The sr.Close method is used to close the StreamReader object.
• ✅ Close: The fs.Close method is used to close the FileStream object.

C# TextReader Methods

There are several commonly used methods of TextReader in C#. Some of them are as follows.

C# TextReader Example with different Methods

Let us take an example to illustrate the different methods of TextReader in C#.

Example

using System;

using System.IO;

class Tpt

{

    static void Main()

    {

        // file exists at the specified path

        string filePath = @" E:\sample.txt ";

        // Using TextReader 

        using (TextReader reader = new StreamReader( filePath) )

        {

            // Read the first line

            string line = reader.ReadLine();

            Console.WriteLine(" The First Line: " + line);

            // Peek at the next character 

            int nextChar = reader.Peek();

            Console.WriteLine("Next Character ASCII Code: " + nextChar );

            // Read the rest of the file

            string remainingText = reader.ReadToEnd ();

            Console.WriteLine(" Remaining Text:\n" + remainingText );

        }

    }

}

Output:

The First Line: Hello C#

Next Character ASCII Code: 10

Remaining Text:

This is a TextReader example.

Enjoy learning!

Explanation:

In this example, we create the TextReader object to read the contents of a text file located at E:\sample.txt. The ReadLine method reads the first line of the file. After that, we are using the Peek method to examine the next character in the file. The ReadToEnd method is used to read all the characters from the current position. Finally, we are using the Console.WriteLine method to print the output.

Features of the TextReader Class in C#

There are several features of the TextReader Class in C#. Some of them are as follows:

• ✅ In the C# programming language, the TextReader class is an abstract class that can provide a platform for reading-based data from text files or streams.
• ✅ It can provide several asynchronous methods, such as ReadAsync, ReadLineAsync, and ReadToEndAsync methods that allow us to perform non-blocking I/O operations.
• ✅ We can use the TextReader class with several input resources, including files or strings, which makes it versatile and flexible for several text-reading operations.
• ✅ We can utilize the TextReader class to read the sequential streams of characters, which makes it suitable to handle text input instead of binary data.
• ✅ It can be defined under the System.IO namespace.

Conclusion

In conclusion, a TextReader is a base class in the C# programming language. It is commonly used to read a character from text sources like files or strings. It provides various methods, such as Read, ReadLine, ReadToEnd, and Peek methods, etc. It helps to read the code easily and safely from different sources. It helps to read the text efficiently, safely, and in a flexible way from different sources.

C# TextReader FAQs

1) What is the TextReader class in C#?

In the C# programming language, the TextReader is a class that is found in the System.IO namespace. It defines a reader text that provides a way to read text or a sequential series of characters. The TextReader class is part of .NET. It is a base class for the StreamReader and StringReader classes.

2) What is the syntax of TextReader in C#?

It has the following syntax.

TextReader reader = new DerivedTextReader();

In this syntax,

• ✅ TextReader: It is an abstract base class in the System.IO namespace.
• ✅ reader: It is the variable name that will hold the reference to the TextReader Object.
• ✅ new: It is the keyword that creates an instance of the derived class.

3) Which classes are derived from TextReader in C#?

In C#, the StreamReader and StringReader classes are derived from TextReader.

4) How do we read a line from a text in C#?

In C#, the ReadLine method of a TextReader is commonly utilized to read one line of the text. The ReadLine method is commonly utilized to read a line of characters from the text reader. It returns the data in a string format.

5) What is the Peek method in C#?

The Peek method is mainly used to read the next character from the text reader without changing the current position. It returns the next character as an integer, or -1, if any characters are not available.