C# Program to count the number of lines in a file

Firstly, create a file using StreamWriter class and add content to it −

using (StreamWriter sw = new StreamWriter("hello.txt")) {    sw.WriteLine("This is demo line 1");    sw.WriteLine("This is demo line 2");    sw.WriteLine("This is demo line 3"); }

Now use the ReadAllLines() method to read all the lines. With that, the Length property is to be used to get the count of lines −

int count = File.ReadAllLines("hello.txt").Length;

Here is the complete code −

Example

 Live Demo

using System; using System.Collections.Generic; using System.IO; public class Program {    public static void Main() {       using (StreamWriter sw = new StreamWriter("hello.txt")) {          sw.WriteLine("This is demo line 1");          sw.WriteLine("This is demo line 2");          sw.WriteLine("This is demo line 3");       }       int count = File.ReadAllLines("hello.txt").Length;       Console.WriteLine("Number of lines: "+count);    } }

Output

Number of lines: 3