What is streamreader and streamwriter class in C#

StreamReader and StreamWriter are found in the System.IO namespace. Both classes are useful when you want to read or write character-based data. Both of these classes deal with Unicode characters. StreamReader derives from the Abstract class "TextReader" and StreamWriter derives from "TextWriter".

C# StreamReader is used to read characters to a stream in a specified encoding. StreamReader.Read method reads the next character or next set of characters from the input stream. StreamReader is inherited from TextReader that provides methods to read a character, block, line, or all content.

The following code example creates a StreamReader and reads a file content one line at a time and displays to the console. If there is an exception, the exception is displayed on the console.

using System;  
using System.IO;  
using System.Text;  
class Program  
{  
static void Main(string[] args)  
{  
// File name  
string fileName = @"C:\Temp\C#CornerMVPsList.txt";  
try  
{  
// Create a StreamReader  
using (StreamReader reader = new StreamReader(fileName))  
{  
string line;  
// Read line by line  
while ((line = reader.ReadLine()) != null)  
{  
Console.WriteLine(line);  
}  
}  
}  
catch (Exception exp)  
{  
Console.WriteLine(exp.Message);  
}  
Console.ReadKey();  
}  
}  

 

StreamWriter class in C# writes characters to a stream in a specified encoding. StreamWriter.Write() method is responsible for writing text to a stream. StreamWriter class is inherited from TextWriter class that provides methods to write an object to a string, write strings to a file, or to serialize XML.

public static void WriteToFile()  
{  
    using (StreamWriter sw = File.CreateText(@"E:\Programming Practice\CSharp\Console\table.tbl"))  
    {  
         sw.WriteLine("Please find the below generated table of 1 to 10");  
         sw.WriteLine("");  
         for (int i = 1; i <= 10; i++)  
         {  
              for (int j = 1; j <= 10; j++)  
              {  
                  sw.WriteLine("{0}x{1}= {2}",i,j,(i*j));  
              }  
              sw.WriteLine("==============");  
         }  
         Console.WriteLine("Table successfully written on file.");  
     }  
}

Note: There are few more method are there to do the same please refer article which written very well by @Mahesh Chand sir.

https://www.c-sharpcorner.com/article/csharp-streamwriter-example/

Streams are used as an intermediate level between the application and the file.

• A StreamReader is used whenever data is required to be read from a file.
• A Streamwriter is used whenever data needs to be written to a file.