Meta.MetaPackage.GetSelectedNodes C# (CSharp) Method

        public IList<IVsHierarchy> GetSelectedNodes()
        {
            // Retrieve shell interface in order to get current selection
            IVsMonitorSelection monitorSelection = GetService(typeof(IVsMonitorSelection)) as IVsMonitorSelection;

            if(monitorSelection == null)
            {
                throw new InvalidOperationException();
            }

            List<IVsHierarchy> selectedNodes = new List<IVsHierarchy>();
            IntPtr hierarchyPtr = IntPtr.Zero;
            IntPtr selectionContainer = IntPtr.Zero;
            try
            {
                // Get the current project hierarchy, project item, and selection container for the current selection
                // If the selection spans multiple hierarchies, hierarchyPtr is Zero
                uint itemid;
                IVsMultiItemSelect multiItemSelect = null;
                ErrorHandler.ThrowOnFailure(monitorSelection.GetCurrentSelection(out hierarchyPtr, out itemid, out multiItemSelect, out selectionContainer));

                // We only care if there are one ore more nodes selected in the tree
                if(itemid != VSConstants.VSITEMID_NIL && hierarchyPtr != IntPtr.Zero)
                {
                    IVsHierarchy hierarchy = Marshal.GetObjectForIUnknown(hierarchyPtr) as IVsHierarchy;

                    if(itemid != VSConstants.VSITEMID_SELECTION)
                        selectedNodes.Add(hierarchy);
                    else if(multiItemSelect != null)
                    {
                        // This is a multiple item selection.

                        //Get number of items selected and also determine if the items are located in more than one hierarchy
                        uint numberOfSelectedItems;
                        int isSingleHierarchyInt;
                        ErrorHandler.ThrowOnFailure(multiItemSelect.GetSelectionInfo(out numberOfSelectedItems, out isSingleHierarchyInt));
                        bool isSingleHierarchy = (isSingleHierarchyInt != 0);

                        // Now loop all selected items and add to the list only those that are selected within this hierarchy
                        Debug.Assert(numberOfSelectedItems > 0, "Bad number of selected itemd");
                        VSITEMSELECTION[] vsItemSelections = new VSITEMSELECTION[numberOfSelectedItems];
                        uint flags = (isSingleHierarchy) ? (uint)__VSGSIFLAGS.GSI_fOmitHierPtrs : 0;
                        ErrorHandler.ThrowOnFailure(multiItemSelect.GetSelectedItems(flags, numberOfSelectedItems, vsItemSelections));
                        foreach (VSITEMSELECTION vsItemSelection in vsItemSelections)
                        {
                            IVsHierarchy node = vsItemSelection.pHier;
                            if(node != null)
                                selectedNodes.Add(node);
                        }
                    }
                }
            }
            finally
            {
                if(hierarchyPtr != IntPtr.Zero)
                {
                    Marshal.Release(hierarchyPtr);
                }
                if(selectionContainer != IntPtr.Zero)
                {
                    Marshal.Release(selectionContainer);
                }
            }

            return selectedNodes;
        }