Question

This is probably a very simple question but I’m a little confused when it comes to working with an object created from a class that contains a field where the type is another class. The part that confuses me is how to populate the field with data from the web form.

For example, if I have a customer class that has a field called contact which is of type Contact, what is the proper way to populate this at the web form level? At present I am doing it as follows and would like to know if this is correct.

This is the code from my customer class and contact is another class.

public class Customer
{
    private string firstName;
    private string lastName'
    private string notes;
    private Contact contact;

    public Customer()
    {
        this.contact = new Contact();
    }

    public string FirstName
    {
        get { return firstName; }
        set { firstName = value; }
    }

    public string LastName
    {
        get { return lastName; }
        set { lastName = value; }
    }
    public string Notes
    {
        get { return notes; }
        set { notes = value; }
    }
    public Contact Contact
    {
        get { return contact; }
        set { contact = value; }
    }
}

Code from my form

private Customer customer;

public WebFormSample()
{
     customer = new AddressBook.Customer();
}
protected void addButton_Click(object sender, EventArgs e)
{
     customer.FirstName = firstName.Text;
     customer.LastName = lastName.Text;
     customer.Contact.Phone = phone.Text;
     customer.Contact.Email = Email.Text;
}

Is this the way I should be working with the contact object or should I have instantiated a contact object on the web form, populate it and then assign it to contact in the customer object or have I got it completely wrong and this should be done in a completely different way?

Hope this makes sense.

Thanks

Answer 1

Did you try the code you posted? Because I would expect customer.Contact to be null as you never created an instance for it.

So you can fix your existing code like this:

customer.Contact = new Contact();
customer.Contact.Phone = phone.Text;
customer.Contact.Email = Email.Text;

Or you can do as you were asking about:

var contact = new Contact();
contact.Phone = phone.Text;
contact.Email = Email.Text;
customer.Contact = contact;

Depending on your needs, either should work.