Microsoft.VisualStudio.Project.FolderNode.IProjectSourceNode C# (CSharp) Method

        int IProjectSourceNode.ExcludeFromProject()
        {
            if (ProjectManager == null || ProjectManager.IsClosed)
            {
                return (int)OleConstants.OLECMDERR_E_NOTSUPPORTED;
            }
            else if (this.IsNonmemberItem)
            {
                return VSConstants.S_OK; // do nothing, just ignore it.
            }

            //using ( WixHelperMethods.NewWaitCursor() )
            //{
            // Check out the project file.
            if (!ProjectManager.QueryEditProjectFile(false))
            {
                throw Marshal.GetExceptionForHR(VSConstants.OLE_E_PROMPTSAVECANCELLED);
            }

            // remove children, if any, before removing from the hierarchy
            for (HierarchyNode child = this.FirstChild; child != null; child = child.NextSibling)
            {
                IProjectSourceNode node = child as IProjectSourceNode;
                if (node != null)
                {
                    int result = node.ExcludeFromProject();
                    if (result != VSConstants.S_OK)
                    {
                        return result;
                    }
                }
            }

            if (ProjectManager != null && ProjectManager.ShowAllFilesEnabled && Directory.Exists(this.Url))
            {
                string url = this.Url;
                this.SetProperty((int)__VSHPROPID.VSHPROPID_IsNonMemberItem, true);
                this.ItemNode.RemoveFromProjectFile();
                this.ItemNode = new ProjectElement(this.ProjectManager, null, true);  // now we have to create a new ItemNode to indicate that this is virtual node.
                this.ItemNode.Rename(url);
                this.ItemNode.SetMetadata(ProjectFileConstants.Name, this.Url);
                this.Redraw(UIHierarchyElements.Icon); // we have to redraw the icon of the node as it is now not a member of the project and shoul be drawn using a different icon.
            }
            else if (this.Parent != null) // the project node has no parentNode
            {
                // this is important to make it non member item. otherwise, the multi-selection scenario would
                // not work if it has any parent child relation.
                this.SetProperty((int)__VSHPROPID.VSHPROPID_IsNonMemberItem, true);

                // remove from the hierarchy
                this.OnItemDeleted();
                this.Parent.RemoveChild(this);
                this.ItemNode.RemoveFromProjectFile();
            }

            // refresh property browser...
            ProjectNode.RefreshPropertyBrowser();
            //}

            return VSConstants.S_OK;
        }