A generic reader for files containing comma separated values.

CsvReader.cs

using System;
using System.IO;

namespace UMNCommonData.IO {
    public class CsvReader {
        public static CsvReader Open(string path, int fieldsRow, int firstDataRow, char separator) {
            string[] lines = File.ReadAllLines(path);
            string[] fields = lines[fieldsRow].Split(separator);
            return new CsvReader(lines, fieldsRow, firstDataRow, separator);
        }

        public readonly string[] Fields;
        readonly string[] _Lines;
        readonly int _FirstDataRow;
        readonly char _Separator;
        const char QUOTE = '\"';

        public int Count => _Lines.Length - _FirstDataRow;

        CsvReader(string[] lines, int fieldsRow, int firstDataRow, char seperator) {
            _Lines = lines;
            _Separator = seperator;
            Fields = GetLine(fieldsRow);
            _FirstDataRow = firstDataRow;
        }

        public string[] GetLine(int index) {
            if (index < 0 || index >= Count) {
                return null;
            }
            string line = _Lines[index + _FirstDataRow];
            string[] data = line.Split(_Separator);
            while (Fields != null && data.Length != Fields.Length) {
                for (int i = 0; i < data.Length - 1; i++) {
                    if (data[i].Length > 1 && data[i][0] == QUOTE && data[i][data[i].Length - 1] != QUOTE) {
                        data[i] = $"{data[i]}{_Separator}{data[i + 1]}";
                        for (int j = i + 2; j < data.Length; j++) {
                            data[j - 1] = data[j];
                        }
                        Array.Resize(ref data, data.Length - 1);
                    }
                }
            }
            for (int i = 0; i < data.Length; i++) {
                if (!string.IsNullOrEmpty(data[i]) && data[i][0] == QUOTE && data[i][data[i].Length - 1] == QUOTE) {
                    if (data[i].Length <= 2) {
                        data[i] = string.Empty;
                    }
                    else {
                        data[i] = data[i].Substring(1, data[i].Length - 2);
                    }
                }
            }
            return data;
        }
    }
}