Populating a List within a class within another class

Question

I apologize for such a simple question, but I've been working on fixing this code for several hours now and I can't make any headway.

I have a project that calls for the usage of three classes: a customer, a employee, and a customer group. The classes are populated from file (.csv) and are then dumped back onto console displaying their contents. The customer group class which contains both a single instance of the employee class and a list of customer(s) as well as a couple of other lists that handle a couple of class unique variables. When dumping out my code I get some Unhandled Exception errors, and debugging has shown that the customer class within the customer group class is null. For all I know, there could be an entire range of other issues, but getting this list of a class populated is the problem.

The code itself is pretty long, so I'm going to try to trim it down for brevity's sake.

The Program bit in question:

while (dataArray[i] == "End")
        {
            int.TryParse(dataArray[i], out temp);
            i++;
            testGrp.Customers.Add(new Customer(temp, dataArray[i++], dataArray[i++], dataArray[i++], dataArray[i++]));
            double.TryParse(dataArray[i], out doubleTemp);
            testGrp.AmountSpent.Add(doubleTemp);
            i++;
            testGrp.SpendingLevel.Add(dataArray[i]);
            i++;
        }

The Customer Group Class:

public CustomerGrp(int groupId, Employee executive, List<Customer> customers,   List<double> amountSpent, List<string> spendingLevel)
    {
        this.groupId = groupId;
        this.executive = executive;
        this.customers = customers;
        this.amountSpent = amountSpent;
        this.spendingLevel = spendingLevel;
    }

And the customer class:

public Customer(int newId, string newName, string newPhoneNumber, string newAddress, string newMarried)
    {
        this.Id = newId;
        this.Name = newName;
        this.PhoneNumber = newPhoneNumber;
        this.Address = newAddress;
        this.Married = newMarried;
    }

dataArray is an array generated from breaking the initial string from the csv file into smaller bits. It's not pretty, but it serves its purpose for now. Prior to this, the groupID and the executive bits have been handled, ending in a i++ to prep for the part shown.

I can get the Employee executive part populated without errors, but populating a list of classes within a class is something I can't quite get my head around. I think I'm doing it right, but most examples I can find don't quite fit this situation. I know my code is anything but pretty, but I'm just trying to establish basic functionality before I start cleaning up. Any help or suggestions would be appreciated.

EDIT

As asked, the message given in console is as follows:

System.NullReferenceException Object Reference Not Set To an instance of the object. at 'line' and 'line'.

The lines are:

DumpContents(testGrp);

and

static void DumpContents(CustomerGrp customerGrp)
    {
        Console.WriteLine("------- Customer Content -------");
        Console.WriteLine("         Id: {0}", customerGrp.GroupId);
        DumpContents(customerGrp.Executive);
        foreach (Customer cust in customerGrp.Customers)
        {
            DumpContents(cust); // <- Exception Error line here
        }
        Console.WriteLine("--------------------------------");
    }

EDIT

Included the overloaded DumpContents function:

static void DumpContents(Employee employee)
     {
        Console.WriteLine("------- Employee Content -------");
        Console.WriteLine("         Id: {0}", employee.Id);
        Console.WriteLine("       Name: {0}", employee.Name);
        Console.WriteLine(" Start Date: {0}", employee.StartDate);
        Console.WriteLine("       Rate: {0}", employee.GetRate());
        Console.WriteLine("      Hours: {0}", employee.GetHours());
        Console.WriteLine("        Pay: {0}", employee.CalcPay());
        Console.WriteLine("     Tenure: {0} Years", employee.GetTenure());
        Console.WriteLine("--------------------------------");
    }

    static void DumpContents(Customer customer)
    {
        Console.WriteLine("------- Customer Content -------");
        Console.WriteLine("            Id: {0}", customer.Id);
        Console.WriteLine("          Name: {0}", customer.Name);
        Console.WriteLine("  Phone Number: {0}", customer.PhoneNumber);
        Console.WriteLine("       Address: {0}", customer.Address);
        Console.WriteLine("Marital Status: {0}", customer.Married);
        Console.WriteLine("--------------------------------");
    }

Answer 1

The line DumpContents(customerGrp.Executive) its recursively calling the DumpContents method - but with an Employee type and then again in a loop with Customer type. The DumpContents must be passed a CustomerGrp.

Simply fix would be to overload the DumpContents method to dump out info for differrent types, eg:

static void DumpContents(CustomerGrp customerGrp)
{
    Console.WriteLine("------- Customer Content -------");
    Console.WriteLine("         Id: {0}", customerGrp.GroupId);
    DumpContents(customerGrp.Executive);
    foreach (Customer cust in customerGrp.Customers)
    {
        DumpContents(cust); // <- Exception Error line here
    }
    Console.WriteLine("--------------------------------");
}


static void DumpContents(Employee employee)
{
    Console.WriteLine("------- Employee Content -------");
    Console.WriteLine("         Id: {0}", employee.Id);
    ...
}


static void DumpContents(Customer customer)
{
    Console.WriteLine("------- CustomerContent -------");
    Console.WriteLine("         Id: {0}", customer.Id);
    ...
}

Answer 2

Make sure you initialize a new instant before the program loop testGrp.Customers = new list ();

And seem like u skip an i in loop

Edit: Wow you are good, you knew I was using my phone to answer the question.

I believe He is getting the error because his customers object was never instantiated. Typically you won't get an error on the DumpContents line because it's a foreach loop unless that object was shared between thread. You probably get the error on the previous line on this line instead: foreach (Customer cust in customerGrp.Customers)

That's why I asked him to make sure the customers objects are instantiated

But then this is just my speculation...