Efficient CSV File Reading and Array Storage in C#

Comma Separated Values (CSV) files are a ubiquitous format for storing tabular data. This article presents two efficient C# methods for reading CSV files and storing their contents in arrays. We’ll explore a manual approach using the StreamReader class and a more streamlined solution leveraging the TextFieldParser class from the Microsoft.VisualBasic.FileIO library.

Table of Contents

• Reading CSV with StreamReader
• Reading CSV with TextFieldParser
• Method Comparison

Reading CSV Files with StreamReader

The StreamReader approach offers granular control over the reading process, enabling customization for diverse CSV formats. However, it demands more manual handling of delimiters and error conditions.

using System;
using System.IO;

public class CsvReaderStreamReader
{
    public static string[][] ReadCsv(string filePath)
    {
        string[][] data = new string[0][]; // Initialize as an empty array
        try
        {
            using (StreamReader reader = new StreamReader(filePath))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    string[] values = line.Split(',');
                    Array.Resize(ref data, data.Length + 1);
                    data[data.Length - 1] = values;
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error reading CSV file: {ex.Message}");
        }
        return data;
    }

    public static void Main(string[] args)
    {
        string filePath = "data.csv"; 
        string[][] csvData = ReadCsv(filePath);

        if (csvData != null)
        {
            foreach (string[] row in csvData)
            {
                Console.WriteLine(string.Join(" ", row));
            }
        }
    }
}

This improved code dynamically resizes the array, avoiding the arbitrary initial size limitation. It also uses string interpolation for cleaner error messages and string.Join for concise output.

Reading CSV Files with TextFieldParser

The TextFieldParser simplifies CSV parsing, especially for complex files with quoted fields or custom delimiters. It handles these intricacies automatically.

using Microsoft.VisualBasic.FileIO;
using System;

public class CsvReaderTextFieldParser
{
    public static string[][] ReadCsv(string filePath)
    {
        string[][] data = new string[0][];
        try
        {
            using (TextFieldParser parser = new TextFieldParser(filePath))
            {
                parser.TextFieldType = FieldType.Delimited;
                parser.SetDelimiters(",");

                while (!parser.EndOfData)
                {
                    string[] fields = parser.ReadFields();
                    Array.Resize(ref data, data.Length + 1);
                    data[data.Length - 1] = fields;
                }
            }
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error reading CSV file: {ex.Message}");
        }
        return data;
    }

    public static void Main(string[] args)
    {
        string filePath = "data.csv";
        string[][] csvData = ReadCsv(filePath);

        if (csvData != null)
        {
            foreach (string[] row in csvData)
            {
                Console.WriteLine(string.Join(" ", row));
            }
        }
    }
}

This code efficiently handles the CSV parsing using TextFieldParser. Remember to add a reference to the Microsoft.VisualBasic assembly in your project.

Method Comparison

Both methods achieve the same outcome, but TextFieldParser is generally preferred for its robustness and ease of use, particularly with complex CSV files. StreamReader offers more control for specialized scenarios, but requires careful error handling and delimiter management.