File.ReadLines foreach JSON String Split TextFieldParser

CSV

A comma-separated values file stores data—it separates each unit with a comma character. In C# we can use built-in methods like Split to parse CSV files.

For maximum performance, a method that handles each byte in a for-loop would be best. But for more clarity, calling the Split method on each line from the file is better.

First example

To run this example, be sure to change the path specified in the Main method to a CSV file that exists. The CSV file will be read and parsed.

Step 1 We specify a string containing the path of the CSV file (relative to the home directory) we want to parse.

Step 2 With File.ReadLines, we handle each line individually, without loading the entire file into an array at once.

Step 3 We call Split to separate the line on all the comma characters. This does not handle escaped characters.

Step 4 With a foreach-loop, we print out each individual field within the line of the CSV file.

using System;
using System.IO;

class Program
{
    static void HandleFile(string path)
    {
        // Step 2: read each line individually with ReadLines.
        foreach (string line in File.ReadLines(path))
        {
            // Step 3: split the line on a comma.
            string[] parts = line.Split(',');

            // Step 4: loop over the lines and do something with them.
            foreach (string value in parts)
            {
                Console.WriteLine("PART: {0}", value);
            }
        }
    }
    static void Main()
    {
        // Step 1: specify the CSV file path.
        HandleFile("programs/example.txt");
    }
}PART: Field1
PART: Field2
PART: Field3
PART: Field4
PART: 100
PART: 200
PART: 300

Summary

There are many ways to handle CSV files in C# programs. With a File.ReadLines and Split, we can handle many files without using any external code.