Display (the correct) data from 2 different XML files in a listbox [closed]

What I need to display is the customer name from the custCollection XML file and tickerSymbol, quantity, and price from the stocklist XML file. I cannot figure out what code to insert to display the correct data from each XML file. Could anyone please help.

public partial class Customer_Stock_Information_Form : Form
{
    StockCollection stkCollection;
    CustomerCollection custCollection;

    public string custName; //field from customer class 
    public string tickerSymbol; //field from the stock class
    public int quantity; //field from the stock class 
    public double currentPrice; //field from the stock 

    public Customer_Stock_Information_Form(StockCollection scPassed, CustomerCollection ccPassed)
    {
        stkCollection = scPassed;
        custCollection = ccPassed;
        InitializeComponent();
    }

    //public Customer_Stock_Information_Form(string custName, string tickerSymbol, int quantity, double currentPrice)
    //{
    //    this.custName = custName;
    //    this.tickerSymbol = tickerSymbol;
    //    this.quantity = quantity;
    //    this.currentPrice = currentPrice;
    //}

    //when this form is loaded, add the customer ID's from each customer into the comboBox..**THIS WORKS**
    private void Customer_Stock_Information_Form_Load(object sender, EventArgs e)
    {            
        for (int i = 0; i < custCollection.Count; i++)
            cboID.Items.Add(custCollection[i].Id);           
    }

    ////////once  a customer ID is selected, display information for that individual in display window..**THIS IS NOT WORKING PROPERLY** **What do I need here????**
    private void cboID_SelectedIndexChanged(string custName, string tickerSymbol, int quantity, double currentPrice)//(object sender, EventArgs e)                           
    {
        for (int i = 0; i < custCollection[cboID.SelectedIndex].Stocklist.Count; i++)//select customer id from cbo Box
            lstCustInfo.Items.Add(custCollection[cboID.SelectedIndex].Stocklist[i]); //display the chosen customer data. THIS IS ONLY SHOWING TICKER chosen in the customer form
            //lstCustInfo.Items.Add(custName, tickerSymbol, quantity, currentPrice);  
            //lstCustInfo.Items.Add(stkCollection(tickerSymbol, quantity,currentPrice));
    }

    // display customer name, ticker symbol, quantity, and price...THIS IS NOT DISPLAYING ANY DATA
    public override string ToString()
    {
        return 
        "Name: " + Name + "  " + "Ticker: " + tickerSymbol + "   " + "Quantity: " + quantity + "  " + "Price: " + currentPrice.ToString("C");
    }

    private void btnExit_Click(object sender, EventArgs e)
    {
        this.Close();
    }