Question

I am using .NET 2.0. I have 2 objects one is: PhoneService and the other one is ChartAccount. The relationship between this to is many to many.

public class PhoneService
{    
    private List<ChartAccount> chartAccounts;
    private ChartAccount chartAccount;    
    public Int64 ID    
    {       get { return id; }     
        set { id = value; }    
    }    
    public bool Add()    { ... }    
    public bool Update()    { ... }
}

public class ChartAccount
{    
    public Int64 ID    
    {       get { return id; }     
        set { id = value; }    
    }    
    public bool Add()    { ... }    
    public bool Update()    { ... }    
    public bool Allocate()    
    {       
        // this will save data for the bridge table only    
    }
}

In my clients, i have the following code:

PhoneService service = new PhoneService(Int64.Parse(dataItem.OwnerTableView.DataKeyValues[dataItem.ItemIndex]["ServiceID"].ToString()));
if (service.ChartAccounts == null)
{
    Allocation allocation = new ChartAccountAllocation(Int64.Parse(drpdwnlstMainChartAccountAllocation.SelectedValue));
    int i=0;
    foreach(AllocationItem allocationItem in allocation.Items)
    {
        service.ChartAccounts[i].Name = allocationItem.Value2;
        service.ChartAccounts[i].SplitPercentage = Decimal.Parse(allocationItem.Value1);
        service.Allocate();
        i++;
     }
}

I got an error on the following line saying that Use the “new” keyword to create an object instance.
service.ChartAccounts[i].Name = allocationItem.Value2;

Because CharAccounts is a collection of ChartAccount object and it’s inside Service object so how do I define this thing then?

Thanks

Answer 1

In your foreach loop, you’re doing service.ChartAccounts[i].Name = allocationItem.Value2, but we already know service.ChartAccounts is null (else you wouldn’t have passed the initial if condition.

Before your foreach loop, you need to initialize service.ChartAccounts, by doing serviceChartAccounts = new List<ChartAccount>(). Then, before you set each value, you need to create a new ChartAccount before you set its Name property.

I’d probably rewrite it something like this:

if (service.ChartAccounts == null)
{
    Allocation allocation = new ChartAccountAllocation(Int64.Parse(drpdwnlstMainChartAccountAllocation.SelectedValue));

    List<ChartAccount> acctList = new List<ChartAccount>();
    foreach(AllocationItem allocationItem in allocation.Items)
    { 
        ChartAccount acct = new ChartAccount();
        acct.Name = allocationItem.Value2;
        acct.SplitPercentage = Decimal.Parse(allocationItem.Value1);
        acctList.Add(acct);
    }
    service.ChartAccounts = acctList;
    service.Allocate(); // I have no idea what this does, so this may be incorrect here
}

The important thing to note is that you create the list, and create the ChartAccount objects before you use them.