System.Windows.Forms.TreeNodeCollection.IndexOfKey C# (CSharp) Method

        public virtual int IndexOfKey(string key)
        {
            if (string.IsNullOrEmpty(key))
                return -1;

            for (int i = 0; i < Count; i++)
                if (SafeCompareStrings(items[i].Name, key, true))
                    return i;

            return -1;
        }

 private TreeNode GetOrAdd(TreeNodeCollection aNodes, string aValue)
 {
     int idx = aNodes.IndexOfKey(aValue);
     if (idx >= 0)
     {
         return aNodes[idx];
     }
     else
     {
         TreeNode node =  aNodes.Add(aValue, aValue);
         node.ExpandAll();
         return node;
     }
 }