难以根据人们的收入和申报状态在文本文件中分配所欠税款

我无法弄清楚如何在我使用的文本文件中进行欠税计算。 当我运行该程序时，它会显示每个人的收入和申报状态，但所欠税款没有显示。

class Program
{
    static void Main(string[] args)
    {
        Customers.CustomerTax(DataIO.TextFileToString(@"C:'Users'Matt'Desktop'tax.txt"));
        foreach (Customers item in Customers._taxList)
        {
            Console.WriteLine(item.ToString());
            FilingStatus fs = (FilingStatus)Enum.Parse(typeof(FilingStatus), "Single");
        }
    }
}  

这是我进行计算的地方

class Customers
{
    String _marriage;
    double _income;
    double _taxOwed;
    private FilingStatus _filingstatus;
    public static List<Customers> _taxList = new List<Customers>();

    public Customers(String marriage, int income)
    {
        Income = income;
        Marriage = marriage;
    }
    public String Marriage
    {
        get { return _marriage; }
        set
        {
            _marriage = value;
        }
    }

    public double Income
    {
        get { return _income; }
        set
        {
            if (value <= 0)
            {
                throw new ArgumentException(String.Format("{0} must be > 0", value));
            }
            _income = value;
        }
    }
    public double CalculateTax()
    {
        double taxOwed = 0.0;
        if (_filingstatus == FilingStatus.Single)
        {
            if (Income <= TaxCalculations.Single10)
            {
                taxOwed = .1 * Income;
            }
            else if (Income <= TaxCalculations.Single15)
            {
                taxOwed = .15 * Income;
            }
            else if (Income <= TaxCalculations.Single25)
            {
                taxOwed = .25 * Income;
            }
            else if (Income <= TaxCalculations.Single28)
            {
                taxOwed = .28 * Income;
            }
            else if (Income <= TaxCalculations.Single33)
            {
                taxOwed = .33 * Income;
            }
            else if (Income <= TaxCalculations.Single35)
            {
                taxOwed = .35 * Income;
            }
            else Console.WriteLine("Derp");
        }
        else if (_filingstatus == FilingStatus.MarriedJoint)
        {
            if (Income <= TaxCalculations.MarriedJoint10)
            {
                taxOwed = .1 * Income;
            }
            else if (Income <= TaxCalculations.MarriedJoint15)
            {
                taxOwed = .15 * Income;
            }
            else if (Income <= TaxCalculations.MarriedJoint25)
            {
                taxOwed = .25 * Income;
            }
            else if (Income <= TaxCalculations.MarriedJoint28)
            {
                taxOwed = .28 * Income;
            }
            else if (Income <= TaxCalculations.MarriedJoint33)
            {
                taxOwed = .33 * Income;
            }
            else if (Income <= TaxCalculations.MarriedJoint35)
            {
                taxOwed = .35 * Income;
            }
            else Console.WriteLine("Derp");
        }
        else if (_filingstatus == FilingStatus.MarriedSeparate)
        {
            if (Income <= TaxCalculations.MarriedSeparate10)
            {
                taxOwed = .1 * Income;
            }
            else if (Income <= TaxCalculations.MarriedSeparate15)
            {
                taxOwed = .15 * Income;
            }
            else if (Income <= TaxCalculations.MarriedSeparate25)
            {
                taxOwed = .25 * Income;
            }
            else if (Income <= TaxCalculations.MarriedSeparate28)
            {
                taxOwed = .28 * Income;
            }
            else if (Income <= TaxCalculations.MarriedSeparate33)
            {
                taxOwed = .33 * Income;
            }
            else if (Income <= TaxCalculations.MarriedSeparate35)
            {
                taxOwed = .35 * Income;
            }
            else Console.WriteLine("Derp");
        }
        else if (_filingstatus == FilingStatus.HeadOfHouse)
        {
            if (Income <= TaxCalculations.HeadOfHouse10)
            {
                taxOwed = .1 * Income;
            }
            else if (Income <= TaxCalculations.HeadOfHouse15)
            {
                taxOwed = .15 * Income;
            }
            else if (Income <= TaxCalculations.HeadOfHouse25)
            {
                taxOwed = .25 * Income;
            }
            else if (Income <= TaxCalculations.HeadOfHouse28)
            {
                taxOwed = .28 * Income;
            }
            else if (Income <= TaxCalculations.HeadOfHouse33)
            {
                taxOwed = .33 * Income;
            }
            else if (Income <= TaxCalculations.HeadOfHouse35)
            {
                taxOwed = .35 * Income;
            }
            else Console.WriteLine("Derp");
        }
        else Console.WriteLine("Not a Valid Filing Status");
        return taxOwed;
    }       

    public static void CustomerTax(String s)
    {
        String[] customersArr = s.Split(''n');
        foreach (string item in customersArr)
        {
            if (item.Equals("")) continue;
            String[] customer = item.Split(',');
            Customers p = new Customers(customer[1], int.Parse(customer[0]));
            _taxList.Add(p);

        }
    }
        public override string ToString()
        {
            return String.Format("Income: {0} Marriage Status: {1} Tax Owed: {2}", _income, _marriage, _taxOwed);
        }
    }
}

流读取器，数据 IO

class DataIO
{
    public static String TextFileToString(String path)
    {
        String output = "";
        String record = "";
        using (StreamReader sr = new StreamReader(path))
        {
            while ((record = sr.ReadLine()) != null)
            {
                output += record + "'n";
            }
        }
        return output;
    }
} 

public override string ToString()
{
     return String.Format("Income: {0} Marriage Status: {1} Tax Owed:", _income, _marriage, _taxOwed);
}

public override string ToString()
{
     return String.Format("Income: {0} Marriage Status: {1} Tax Owed: {2}", _income, _marriage, _taxOwed);
}