A simplistic date range parser class in C#

DateRangeParser.cs

class DateRangeParser
{
    #region Global variables

    private string[] _wordBankSplitParams = new string[] { " ", "and" };
    private List<string> _monthList = new List<string>()
    {
        "January",
        "Feburary",
        "March",
        "April",
        "May",
        "June",
        "July",
        "August",
        "September",
        "October",
        "November",
        "December"
    };

    #endregion

    public DateRangeParser() {}

    /// <summary>
    /// Parses a date range string and returns the start date and end date
    /// Sample expected date range string format:
    /// - 19 November - 31 December 2016
    /// - 07 December 2016
    /// - 12 and 13 December 2016
    /// - 14 December 2016
    /// - 22 December 2016
    /// - 7 December 2016
    /// - 01 - 31 January 2017
    /// </summary>
    /// <param name="dateRangeString">String to parse</param>
    /// <returns>List containing start date and end date</returns>
    public List<DateTime> parseDateRangeString(string dateRangeString)
    {
        List<DateTime> parsedDates = new List<DateTime>();

        try
        {
            // Generate word bank and proximity table
            // - Word bank is an array of WordBankObjects found in the input string.
            // - Proximity table is a two-dimensional array. For each word (the subject) in the word bank,
            //      an array of integers exists indicating the distance of each element to the subject.
            string[] wordBankArray = dateRangeString.Split(_wordBankSplitParams, StringSplitOptions.RemoveEmptyEntries);

            List<WordBankObject> wordBankObjList = GenerateWordBank(dateRangeString, wordBankArray);
            List<List<int>> proximityTable = GenerateProximityTable(wordBankObjList);
            List<List<WordBankObject>> rankedWordBankObjTable = GenerateRankedWordBankObjTable(proximityTable, wordBankObjList);

            #region Use word bank to find closest year and month

            for (int i = 0; i < wordBankObjList.Count; i++)
            {
                if (wordBankObjList[i].Type == WordBankObjectType.Date)
                {
                    bool foundYear = false;
                    bool foundMonth = false;
                    string closestYearString = string.Empty;
                    string closestMonthString = string.Empty;

                    for (int j = 0; j < rankedWordBankObjTable[i].Count; j++)
                    {
                        if (rankedWordBankObjTable[i][j].Type == WordBankObjectType.Year && foundYear == false)
                        {
                            closestYearString = rankedWordBankObjTable[i][j].Word;
                            foundYear = true;
                        }
                        else if (rankedWordBankObjTable[i][j].Type == WordBankObjectType.Month && foundMonth == false)
                        {
                            closestMonthString = rankedWordBankObjTable[i][j].Word;
                            foundMonth = true;
                        }

                        if (foundYear && foundMonth)
                        {
                            string dateStringtoParse = String.Join(" ", new[] { wordBankObjList[i].Word, closestMonthString, closestYearString });
                            DateTime parsedDate;
                            DateTime.TryParse(dateStringtoParse, out parsedDate);
                            parsedDates.Add(parsedDate);

                            foundMonth = false;
                            foundYear = false;
                            break;
                        }
                    }
                }

                #endregion

            }
        }
        catch (Exception ex)
        {
            LogEvent(TraceLevel.Error, "Error in parsing date range from Scheduled Outages table", ex);
        }

        return parsedDates;
    }

    /// <summary>
    /// Generate a ranked word bank table
    /// </summary>
    /// <param name="proximityTable"></param>
    /// <param name="wordBankObjList"></param>
    /// <returns>Ranked word bank table</returns>
    private List<List<WordBankObject>> GenerateRankedWordBankObjTable(List<List<int>> proximityTable, List<WordBankObject> wordBankObjList)
    {
        List<List<WordBankObject>> rankedWordBankObjTable = new List<List<WordBankObject>>();
        foreach (var proximityColumn in proximityTable)
        {
            List<WordBankObject> rankedWordBankObjList = new List<WordBankObject>();
            for (int i = 0; i <= proximityColumn.Max(); i++)
            {
                for (int j = 0; j < proximityColumn.Count; j++)
                {
                    if (proximityColumn[j] == i)
                    {
                        rankedWordBankObjList.Add(wordBankObjList[j]);
                    }
                }
            }

            rankedWordBankObjTable.Add(rankedWordBankObjList);
        }

        return rankedWordBankObjTable;
    }

    /// <summary>
    /// Generate a proximity table
    /// - Proximity table is a two-dimensional array. For each word (the subject) in the word bank,
    ///      an array of integers exists indicating the distance of each element to the subject.
    /// </summary>
    /// <param name="wordBankObjList"></param>
    /// <returns>Proximity table</returns>
    private List<List<int>> GenerateProximityTable(List<WordBankObject> wordBankObjList)
    {
        List<List<int>> proximityTable = new List<List<int>>();

        for (int i = 0; i < wordBankObjList.Count(); i++)
        {
            List<int> proximityColumn = new List<int>();
            for (int j = 0; j < wordBankObjList.Count(); j++)
            {
                proximityColumn.Add(Math.Abs(wordBankObjList[i].Index - wordBankObjList[j].Index));
            }
            proximityTable.Add(proximityColumn);
        }

        return proximityTable;
    }

    /// <summary>
    /// Generate a word bank
    /// - Word bank is an array of WordBankObjects found in the input string.
    /// </summary>
    /// <param name="dateRangeString"></param>
    /// <param name="wordBankArray"></param>
    /// <returns>Word bank</returns>
    private List<WordBankObject> GenerateWordBank(string dateRangeString, string[] wordBankArray)
    {
        List<WordBankObject> wordBankObjList = new List<WordBankObject>();

        try
        {
            for (int i = 0; i < wordBankArray.Count(); i++)
            {
                string word = wordBankArray[i];
                int wordInt;
                WordBankObject wordBankObj;

                if (Int32.TryParse(word, out wordInt))
                {
                    switch (word.Length)
                    {
                        case 1:
                        case 2:
                            wordBankObj = new WordBankObject(word, WordBankObjectType.Date, i);
                            break;
                        case 4:
                            wordBankObj = new WordBankObject(word, WordBankObjectType.Year, i);
                            break;
                        default:
                            Exception ex = new Exception("Failed to parse word " + word + " from " + dateRangeString + " because of unknown type");
                            throw ex;
                    }
                }
                else
                {
                    if (_monthList.Contains(word))
                    {
                        wordBankObj = new WordBankObject(word, WordBankObjectType.Month, i);
                    }
                    else if (word == "-")
                    {
                        wordBankObj = new WordBankObject(word, WordBankObjectType.Other, i);
                    }
                    else
                    {
                        Exception ex = new Exception("Failed to parse word " + word + " from " + dateRangeString + " because of unknown type");
                        throw ex;
                    }
                }

                wordBankObjList.Add(wordBankObj);
            }
        }
        catch (Exception ex)
        {
            LogEvent(TraceLevel.Error, "Error in generating word bank", ex);
        }

        return wordBankObjList;
    }
}