Question

So I am getting a fun compiler error! I’ll paste it down here as well: “the type (my class) must be non-nullable type in order to use as a parameter ‘T’ in the generic method”

This doesn’t make sense to me since my method is not generic. Here is how I am calling the offending code:

Item? inputtedItem = SearchProduct(txtProduct.Text);

Meanwhile, here is the definition of SearchProduct:

        private Item? SearchProduct(string product)
    {
        //If this is the first item to be entered into the inventory
        if (_inventory == null || _inventory._productList.Count == 0)
        {
            return null;
        }
        //Return the Item's instance if it appears in the inventory.  Otherwise return null.
        return _inventory[product];
    }

I suppose I’ll add the indexer from my inventory class in here for good measure:

       public Item this[string i]
    {
        get
        {
            Item returnItem;
            _productList.TryGetValue(i, out returnItem);
            return returnItem;
        }
        set
        {
            _productList.Add(i, value);
        }
    }

Does anybody know what’s wrong?

Thank you for the help.

Answer 1

I don’t think you need the ? in Item?. If Item is a custom defined class, it will be nullable by default.