How to Read and Write to a File in C#

1. Write Data to a File With the File.WriteAllText() Method in C#
2. Read Data From a File With the File.ReadAllText() Method in C#
3. Write Data to a File With the StreamWriter Class in C#
4. Read Data From a File With the StreamReader Class in C#

This tutorial will discuss methods to read from and write data to a file in C#.

Write Data to a File With the File.WriteAllText() Method in C#

The File class provides functionality for file handling in C#. The File.WriteAllText(path) method can be used to write some string to a file in the path path. The following code example shows us how to write data to a file with the File.WriteAllText() function in C#.

using System;
using System.IO;

namespace write_to_a_file {
  class Program {
    static void Main(string[] args) {
      string path = "C:\\File\\file.txt";
      string Text = "Hello, Hi, ByeBye";
      File.WriteAllText(path, Text);
    }
  }
}

file.txt contents:

Hello, Hi, ByeBye

In the above code, we created a text file file.txt inside the path C:\File and wrote the string variable Text to the file.txt file with the File.WriteAllText(path, Text) function in C#.

Read Data From a File With the File.ReadAllText() Method in C#

The File.ReadAllText() method can be used to read data from a file in the form of a string variable. The File.ReadAllText() method takes the path of the file as a parameter and returns the contents of the file in string data type. The following code example shows us how to read data from a file with the File.ReadAllText() method in C#.

using System;
using System.IO;

namespace write_to_a_file {
  class Program {
    static void Main(string[] args) {
      string path = "C:\\File\\file.txt";
      string readText = File.ReadAllText(path);
      Console.WriteLine(readText);
    }
  }
}

Output:

Hello, Hi, ByeBye

In the above code, we read all the data previously written to the file.txt file inside the C:\File directory with the File.ReadAllText(path) method and displayed it to the user.

Write Data to a File With the StreamWriter Class in C#

The StreamWriter class is used to write data to a stream in a particular encoding in C#. The StreamWrite.WriteLine() method can be used to write a string variable to a file. The following code example shows us how to write data to a file with the StreamWriter.WriteLine() method in C#.

using System;
using System.IO;

namespace write_to_a_file {
  class Program {
    static void Main(string[] args) {
      string path = "C:\\File\\file.txt";
      string Text = "Hello and Welcome";
      using (StreamWriter writetext = new StreamWriter(path)) {
        writetext.WriteLine(Text);
      }
    }
  }
}

file.txt contents:

Hello and Welcome

In the above code, we created an object of the StreamWriter class and wrote the string variable Text to the file.txt file inside the C:\File directory with the writetext.WriteLine(Text) function in C#.

Read Data From a File With the StreamReader Class in C#

The StreamReader class is used to read data from a stream in a particular encoding in C#. The StreamReader.ReadLine() method can be used to read string data from a file. The following code example shows us how to read data from a file with the StreamReader.ReadLine() method in C#.

using System;
using System.IO;

namespace write_to_a_file {
  class Program {
    static void Main(string[] args) {
      string path = "C:\\File\\file.txt";
      using (StreamReader readtext = new StreamReader(path)) {
        string readText = readtext.ReadLine();
        Console.WriteLine(readText);
      }
    }
  }
}

Output:

Hello and Welcome

In the above code, we created an object of the StreamReader class and read all the data previously written to the file.txt file inside the C:\File directory with the readtext.ReadLine() function and displayed it to the user.