C# Taschenrechner Klasse

Erhielt ich diese Hausaufgabe, die ich habe eine harte Zeit mit. Die form wurde geschrieben und wir hatten die zum schreiben der Klasse. Derzeit, wenn ich das Programm starte meine equals-Taste scheint nicht zu funktionieren. Ich bin mir nicht sicher warum, und ich Frage mich, wenn mir jemand helfen könnte zu verstehen, was ich bin fehlt. Ich glaube, dass ich geschrieben habe, meiner Klasse richtig. In meinem Kopf, was passiert ist, ist der Rechner Aufruf des "currentValue" ich bin also ständig zu aktualisieren mit der Methode, die ich benutze in meinem Betreiber.

Bin ich in die richtige Richtung?

... Und warum nicht meine ist-gleich-Taste ruft den aktuellen Wert. Das Letzte mal lief ich das, wenn ich getippt, 9 + 3 + dann mein display bevölkern mit 12, und warten Sie für mich, um in der nächsten Nummer. So in der Theorie, warum würde nicht meine ist-gleich-Taste laden Sie die Antwort? Ich glaube, ich rufe das richtige Element, das ich noch immer meinen ersten Eintrag. Zum Beispiel, wenn ich getippt, 9 + 9 und hit = ich erhalte 9.

Hier ist der Rechner code (der Teil zur Verfügung gestellt):

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Calculator
{
public partial class frmCalculator : Form
{
    public frmCalculator()
    {
        InitializeComponent();
    }

    //The following fields are used to store the value that's currently
    //displayed by the calculator. displayString is a string value that's
    //constructed as the user clicks numeric keys and the decimal and +/-
    //key. The Convert.ToDecimal method is then used to convert this to a decimal
    //field that's stored in displayValue.
    private string displayString;
    private decimal displayValue;

    //The following bool fields are used to control numeric entry.
    //newValue indicates whether the calculator is ready to receive a
    //new numeric value. Once the user clicks a digit button, newValue is
    //set to false. When the user clicks a button that "enters" the value, 
    //such as Add or Equals, newValue is set to true so the user can enter 
    //another value.
    //decimalEntered is used to restrict the entry to a single decimal point.
    //It is set to true whenever newValue is set to true, and it is set to 
    //false whenever the user clicks the decimal point button.
    private bool newValue;
    private bool decimalEntered;

    private Calculator calc = new Calculator();

    private void Form1_Load(object sender, System.EventArgs e)
    {
        displayValue = 0;
        displayString = displayValue.ToString();
        newValue = true;
        decimalEntered = false;
    }

    //This method handles the 0 through 9 keys, appending the digit clicked
    //to the displayString field. 
    private void btnNumber_Click(object sender, System.EventArgs e)
    {
        if (newValue)
        {
            displayString = "";
            newValue = false;
        }
        displayString += ((Button)sender).Tag.ToString();
        displayValue = Convert.ToDecimal(displayString);
        txtDisplay.Text = displayValue.ToString();
    }

    //This method removes the last character from the displayString field.
    private void btnBackSpace_Click(object sender, System.EventArgs e)
    {
        if (displayString.Length > 1)
        {
            displayString = displayString.Substring(0, displayString.Length - 1);
            displayValue = Convert.ToDecimal(displayString);
            txtDisplay.Text = displayValue.ToString();
        }
        else
        {
            displayString = "";
            displayValue = 0;
            txtDisplay.Text = displayValue.ToString();
        }

    }

    private void btnClear_Click(object sender, System.EventArgs e)
    {
        calc.Clear();
        displayString = "";
        displayValue = 0;
        txtDisplay.Text = displayValue.ToString();
        newValue = true;
        decimalEntered = false;
    }

    //This method appends a decimal point to the displayString field if the
    //user has not already entered a decimal point.
    private void btnDecimal_Click(object sender, System.EventArgs e)
    {
        if (newValue)
        {
            displayString = "0";
            newValue = false;
        }
        if (!decimalEntered)
        {
            displayString += ".";
            displayValue = Convert.ToDecimal(displayString);
            txtDisplay.Text = displayValue.ToString();
            decimalEntered = true;
        }
    }

    private void btnSign_Click(object sender, System.EventArgs e)
    {
        displayValue = -displayValue;
        txtDisplay.Text = displayValue.ToString();
    }

    private void btnAdd_Click(object sender, System.EventArgs e)
    {
        calc.Add(displayValue);
        newValue = true;
        decimalEntered = false;
        displayValue = calc.CurrentValue;
        txtDisplay.Text = displayValue.ToString();
    }

    private void btnSubtract_Click(object sender, System.EventArgs e)
    {
        calc.Subtract(displayValue);
        newValue = true;
        decimalEntered = false;
        displayValue = calc.CurrentValue;
        txtDisplay.Text = displayValue.ToString();
    }

    private void btnMultiply_Click(object sender, System.EventArgs e)
    {
        calc.Multiply(displayValue);
        newValue = true;
        decimalEntered = false;
        displayValue = calc.CurrentValue;
        txtDisplay.Text = displayValue.ToString();
    }

    private void btnDivide_Click(object sender, System.EventArgs e)
    {
        calc.Divide(displayValue);
        newValue = true;
        decimalEntered = false;
        displayValue = calc.CurrentValue;
        txtDisplay.Text = displayValue.ToString();
    }

    private void btnSqrt_Click(object sender, System.EventArgs e)
    {
        calc.SquareRoot(displayValue);
        displayValue = calc.CurrentValue;
        txtDisplay.Text = displayValue.ToString();
    }

    private void btnReciprocal_Click(object sender, System.EventArgs e)
    {
        try
        {
            calc.Reciprocal(displayValue);
            displayValue = calc.CurrentValue;
            txtDisplay.Text = displayValue.ToString();
        }
        catch (DivideByZeroException)
        {
            displayValue = 0;
            txtDisplay.Text = "Cannot divide by zero.";
            newValue = true;
            decimalEntered = false;
        }
    }

    private void btnEquals_Click(object sender, System.EventArgs e)
    {
        try
        {
            if (newValue)
                calc.Equals();
            else
                calc.Equals(displayValue);
            displayValue = calc.CurrentValue;
            txtDisplay.Text = displayValue.ToString();
            newValue = true;
            decimalEntered = false;
        }
        catch (DivideByZeroException)
        {
            displayValue = 0;
            txtDisplay.Text = "Cannot divide by zero.";
            newValue = true;
            decimalEntered = false;
        }
    }

}

}

Hier ist meine Klasse (Der Teil, den ich schrieb):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Calculator
{
public class Calculator
{

    public Decimal displayValue;
    public Decimal currentValue;

     public void Add(Decimal displayValue)
    {

        currentValue += displayValue;

    }

     public void Subtract(Decimal displayValue)
     {
         currentValue -= displayValue;
     }

     public void Multiply(Decimal displayValue)
     {
         currentValue *= displayValue;
     }


     public void Divide(Decimal displayValue)
     {
         currentValue /= displayValue;
     }

     public void SquareRoot(Decimal displayValue)
     {
         currentValue = (decimal)Math.Sqrt(Convert.ToDouble(displayValue));
     }

     public void Reciprocal(Decimal displayValue)
     {
         currentValue = 1 / displayValue;
     }

     public decimal Equals()
     {
         return currentValue;
     }


     public void Clear()
     {
         currentValue = 0;
         displayValue = 0;
     }

     public decimal CurrentValue
     {
       get
          {
           return currentValue;
          }

     }
}

}