Microsoft.VisualStudio.Project.ProjectNode.AddDependentFileNode C# (CSharp) Method

        protected virtual HierarchyNode AddDependentFileNode(IDictionary<String, MSBuild.ProjectItem> subitems, string key)
        {
            if (subitems == null)
            {
                throw new ArgumentNullException("subitems");
            }

            MSBuild.ProjectItem item = subitems[key];
            subitems.Remove(key);

            HierarchyNode newNode;
            HierarchyNode parent = null;

            string dependentOf = item.GetMetadataValue(ProjectFileConstants.DependentUpon);
            Debug.Assert(String.Compare(dependentOf, key, StringComparison.OrdinalIgnoreCase) != 0, "File dependent upon itself is not valid. Ignoring the DependentUpon metadata");
            if (subitems.ContainsKey(dependentOf))
            {
                // The parent item is an other subitem, so recurse into this method to add the parent first
                parent = AddDependentFileNode(subitems, dependentOf);
            }
            else
            {
                // See if the parent node already exist in the hierarchy
                uint parentItemID;
                string path = Path.Combine(this.ProjectFolder, dependentOf);
                ErrorHandler.ThrowOnFailure(this.ParseCanonicalName(path, out parentItemID));
                if (parentItemID != (uint)VSConstants.VSITEMID.Nil)
                    parent = this.NodeFromItemId(parentItemID);
                Debug.Assert(parent != null, "File dependent upon a non existing item or circular dependency. Ignoring the DependentUpon metadata");
            }

            // If the parent node was found we add the dependent item to it otherwise we add the item ignoring the "DependentUpon" metatdata
            if (parent != null)
                newNode = this.AddDependentFileNodeToNode(item, parent);
            else
                newNode = this.AddIndependentFileNode(item);

            return newNode;
        }