CODEWITHSUNDEEP
c#class
user2246303
user2246303

Reputation: 27

Object reference not set to an instance of an object with class

I have a situation where I have defined a class within a class, resembling the following:

    public partial class ProdData 
    {
    private string prodID;
    private string Description;

    ...and so on until I get to

    private ProdDataChildren[] childItemsField; 
    }

ProdDataChildren is it's own class, which I am using to identify sub-products that may belong to the parent product, hence the array.

In the main part of my program I have a loop that reads in records, sort of like:

        while (myReader.Read())
        {
            ProdData ProductDataIn = new ProdData();
            ProductDataIn.ID = "values assigned here";

until I get to the point there I want to assign a child, this is where I am getting the error "Object reference not set to an instance of an object", using the following statement

         ProductDataIn.ChildItems[i].ProdID = "string variable here";
        }

I beleive the cause of the error is something to do with the current ChildItems being set to null, but how am I supposed to assign a value to it? Do I need to instantiate and instance of the child item somehow and how would I do this?

Any help would be appreciated, I realize this might be a no brainer for some.

Upvotes: 0

Views: 860

Answers (2)

Justin
Justin

Reputation: 3397

You only declared the variable. You didn't create a new instance of the array so you are trying to access an object that hasn't yet been created.

Upvotes: 1

MarcinJuraszek
MarcinJuraszek

Reputation: 125630

First of all, you have to initialize your field before assigning anything to that collection. I would suggest using List instead of Array:

public partial class ProdData 
{

...and so on until I get to

private List<ProdDataChildren> childItemsField = new List<ProdDataChildren>(); 
}

With List you'll be able to do following:

ProductDataIn.ChildItems.Add(new ProdDataChildren() { ProdID = "string variable here" });

Upvotes: 2

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