System.Configuration.ConfigurationElementCollection.RealIndexOf C# (CSharp) Method

        internal int RealIndexOf(ConfigurationElement element) {
            int index = 0;
            Object key = GetElementKeyInternal(element);
            foreach (Entry entry in _items) {
                if (CompareKeys(key, entry.GetKey(this))) {
                    return index;
                }
                index++;
            }
            return -1;
        }