Question

CS0123: No overload for ‘addItems’ matches delegate ‘System.EventHandler’

protected void addItems(System.EventHandler e)
        {
            DropDownList numDropDown = (DropDownList) Page.FindControl("DropDownNum");

            foreach (numOption option in numConfigManager.numConfig.numOptions.Options)
            {
                numDropDown.Items.Add(option.Value);
            }
        }

Answer 1

You haven’t shown anything called printListItems so it’s not clear where that comes in, but I suspect you just want to change the signature of your method to:

protected void addItems(object sender, EventArgs e)

… although you should also rename it to AddItems to follow .NET naming conventions.