Question

I get an exception on the List.Add line when trying to run this code:

        string searchText = searchByInterestBox.Text;
        List<string> checkedItems = null;

        if (m_BusinessLogic != null)    
        {
            if (searchText != string.Empty)  
            {
                try
                {
                    interestResultBox.Items.Clear();
                    foreach (var itemChecked in InterestsCheckedListBox.CheckedItems)
                    {
                        checkedItems.Add(itemChecked.ToString());
                    }

While debugging, when reaching the last line of code (checkedItems.Add) it says “Object Reference not set to an instance of an object”

Any idea what did I do wrong with the string list?

Thanks a lot.
Itzik.

Answer 1

checkedItems is null, so you are getting an exception. You need to initialize it.

Instead of:

List<string> checkedItems = null;

Do:

IList<string> checkedItems = new List<string>();