Question

THIS IS HOMEWORK: I have a program that consists of two winforms and three classes. The program does the work it is supposed to do for the main form and displays it appropriately onto the textbox of the main form. In addition to displaying the information, it is also saved to a string list. The data consists of order information.

The string list passes that information along to a method in another class and stores it in a list as it is supposed to do. After this is done, I press a button which opens up another form. In this form I enter an order number. What is supposed to happen is that a method compares the order number entered with the row number of the list and return that information, whereupon it is displayed in the textbox of the second form.

That is what is supposed to happen. Instead, when it is time to compare the order number with the row number of the list, the list data is gone and I cannot figure out why. Here is my code that pertains:

 private void btnPaymentButton_Click(object sender, EventArgs e)
    {            
        amountPaid = double.Parse(this.txtAmountPaid.Text);
        orderObject.GetChangeDue(orderObject.TotalAmountDue, amountPaid);                   

        this.txtNumberOfPizzaOrdered.Clear();
        this.txtNumberOfCokesOrdered.Clear();
        this.txtAmountDue.Clear();
        this.txtAmountPaid.Clear();
        this.lblYourOrder.Visible = true;
        this.rtxtYourOrder.Visible = true;
        this.rtxtYourOrder.Text = orderObject.OrderSummary(amountPaid);

        //storeOrderObject = new DailySummary(orderObject.OrderSummary(amountPaid));

        storeOrderObject = new DailySummary(this.rtxtYourOrder.Text);           
    }     

private void btnDailySummary_Click(object sender, EventArgs e)
    {
        DailySummaryForm form = new DailySummaryForm();
       // this.Visible = false;
        form.Show();
    }

........

public class DailySummary
{
    //declare variables
    int numberOfCokes = 0,
        numberOfPizzas = 0,
        totalOfCokes = 0,
        totalOfPizzas = 0,            
        orderNumberRequest = 0;        

    string orderFromForm1 = "",
           getAllTheOrders = "",
           getAnOrder = "";

    List<string> pizzaOrderList = new List<string>();

    public DailySummary(string orderForm)
    {
        orderFromForm1 = orderForm;
        StoreOrder(orderFromForm1);
    }

    public DailySummary(int orderRequest)
    {
        orderNumberRequest = orderRequest;
        GetOrder(OrderNumberRequest);
    }

public int OrderNumberRequest
    {
        get
        {
            return this.orderNumberRequest;
        }
    }        

//store order
    public void StoreOrder(string orderFromForm1)
    {
        pizzaOrderList.Add(orderFromForm1);
    }

    //get the order
    public string GetOrder(int OrderNumberRequest)
    {
        for (int row = 0; row < pizzaOrderList.Count; row++)
        {
            if (row == (OrderNumberRequest - 1))
            {
                getAnOrder = pizzaOrderList[row];
            }
        }
        return getAnOrder;
    }

........

public partial class DailySummaryForm : Form
{
    int orderNumberRequest = 0;
    //instantiate a from object
    OrderForm formObject;
    DailySummary summaryObject;

    public DailySummaryForm()
    {
        InitializeComponent();
    }

    private void btnOrderNumberButton_Click(object sender, EventArgs e)
    {
        orderNumberRequest = int.Parse(this.txtOrderNumber.Text);
        summaryObject = new DailySummary(orderNumberRequest);

        this.rtxtDisplayOutput.Visible = true;
        this.rtxtDisplayOutput.Text = summaryObject.GetAnOrder;
    }

Answer 1

In your method btnPaymentButton_Click you create an instance of the DailySummary class, then later on when your in the DailySummaryForm you create a new instance of the DailySummary Class.

These instances are separate and therefore do not share the same values.

As your not persisting values to the DB you’ll probably want to:

1. look into making your DailySummary Static (which will make it accessable throughout your
   winform application). (It’s not typically good practice to have too many global (static) variables hanging around, but without a persistence engine where you can store your Daily Summary you need a common place to look it up.
2. Pass the initialized instance of the DailySummary class to your DailySummaryForm. (The DailySummaryForm could expose a public property. The drawback of this method is if your switching between both forms and each form modified your summary class, your going to constantly have to pass it back and forth between the forms.