Selectors for page builder components

        // Assigns a selector component to the 'Images' property
        [EditingComponent(MediaFilesSelector.IDENTIFIER)]
        // Configures the media library from which you can select files in the selector
        [EditingComponentProperty(nameof(MediaFilesSelectorProperties.LibraryName), "Graphics")]
        // Limits the maximum number of files that can be selected at once
        [EditingComponentProperty(nameof(MediaFilesSelectorProperties.MaxFilesLimit), 5)]
        // Configures the allowed file extensions for the selected files
        [EditingComponentProperty(nameof(MediaFilesSelectorProperties.AllowedExtensions), ".gif;.png;.jpg;.jpeg")]
        // Returns a list of media files selector items (objects that contain the GUIDs of selected media files)
        public IEnumerable<MediaFilesSelectorItem> Images { get; set; } = Enumerable.Empty<MediaFilesSelectorItem>();

        private readonly IMediaFileInfoProvider mediaFileInfo;
        private readonly IComponentPropertiesRetriever componentPropertiesRetriever;
        private readonly ISiteService siteService;
 
        public MediaFilesSelectorExample(IMediaFileInfoProvider mediaFileInfo, 
                                         IComponentPropertiesRetriever componentPropertiesRetriever,
                                         ISiteService siteService)
        {
            this.mediaFileInfo = mediaFileInfo;
            this.componentPropertiesRetriever = componentPropertiesRetriever;
            this.siteService = siteService;
        }
 
        public ActionResult Index()
        {
            // Retrieves the GUID of the first selected media file from the 'Images' property
            Guid guid = componentPropertiesRetriever.Retrieve<CustomWidgetProperties>().Images.FirstOrDefault()?.FileGuid ?? Guid.Empty;
            // Retrieves the MediaFileInfo object that corresponds to the selected media file GUID
            MediaFileInfo mediaFile = mediaFileInfo.Get(guid, siteService.CurrentSite.SiteID);
 
            string url = String.Empty;
            if (mediaFile != null)
            {
                // Retrieves an URL of the selected media file
                url = MediaLibraryHelper.GetDirectUrl(mediaFile);
            }
 
            // Custom logic...
 
            return View();
        }

        // Assigns a selector component to the Pages property
        [EditingComponent(PageSelector.IDENTIFIER)]
        // Limits the selection of pages to a subtree rooted at the 'Products' page
        [EditingComponentProperty(nameof(PageSelectorProperties.RootPath), "/Products")]
        // Returns a list of page selector items (node GUIDs)
        public IEnumerable<PageSelectorItem> Pages { get; set; } = Enumerable.Empty<PageSelectorItem>();

        private readonly IPageRetriever pagesRetriever;
        private readonly IComponentPropertiesRetriever componentPropertiesRetriever;
 
        public PageSelectorExample(IPageRetriever pagesRetriever, IComponentPropertiesRetriever componentPropertiesRetriever)
        {
            this.pagesRetriever = pagesRetriever;
            this.componentPropertiesRetriever = componentPropertiesRetriever;
        }
 
        public ActionResult Index()
        {
            // Retrieves the node GUID of the selected page from the 'Pages' property
            Guid? selectedPageGuid = componentPropertiesRetriever.Retrieve<CustomWidgetProperties>().Pages.FirstOrDefault()?.NodeGuid;
            // Retrieves the page that corresponds to the selected GUID
            TreeNode page = pagesRetriever.Retrieve<TreeNode>(query => query
                                .WhereEquals("NodeGUID", selectedPageGuid)
                                .TopN(1))
                                .FirstOrDefault();
 
            // Custom logic...
 
            return View();
        }

        // Assigns a selector component to the 'PagePaths' property
        [EditingComponent(PathSelector.IDENTIFIER)]
        // Limits the selection of pages to a subtree rooted at the 'Products' page
        [EditingComponentProperty(nameof(PathSelectorProperties.RootPath), "/Products")]
        // Returns a list of path selector items (page paths)
        public IEnumerable<PathSelectorItem> PagePaths { get; set; } = Enumerable.Empty<PathSelectorItem>();

        private readonly IPageRetriever pagesRetriever;
        private readonly IComponentPropertiesRetriever componentPropertiesRetriever;
 
        public PathSelectorExample(IPageRetriever pagesRetriever, IComponentPropertiesRetriever componentPropertiesRetriever)
        {
            this.pagesRetriever = pagesRetriever;
            this.componentPropertiesRetriever = componentPropertiesRetriever;
        }
 
        public ActionResult Index()
        {
            // Retrieves the node alias path of the selected page from the 'PagePaths' property
            string selectedPagePath = componentPropertiesRetriever.Retrieve<CustomWidgetProperties>().PagePaths.FirstOrDefault()?.NodeAliasPath;
            // Retrieves the page that corresponds to the selected node alias path
            TreeNode page = pagesRetriever.Retrieve<TreeNode>(query => query
                                .Path(selectedPagePath)
                                .TopN(1))
                                .FirstOrDefault();
 
            // Custom logic...
 
            return View();
        }

        // Assigns a selector component to the 'Attachments' property
        [EditingComponent(AttachmentSelector.IDENTIFIER)]
        // Limits the maximum number of attachments that can be selected at once
        [EditingComponentProperty(nameof(AttachmentSelectorProperties.MaxFilesLimit), 3)]
        // Configures the allowed file extensions for the selected attachments
        [EditingComponentProperty(nameof(AttachmentSelectorProperties.AllowedExtensions), ".gif;.png;.jpg;.jpeg")]
        // Returns a list of attachment selector items (attachment objects)
        public IEnumerable<AttachmentSelectorItem> Attachments { get; set; } = Enumerable.Empty<AttachmentSelectorItem>();

        private readonly IComponentPropertiesRetriever propertiesRetriever;
        private readonly ISiteService siteService;
        private readonly IPageAttachmentUrlRetriever attachmentUrlRetriever;
 
        public AttachmentSelectorExample(IComponentPropertiesRetriever propertiesRetriever,
                                         ISiteService siteService,
                                         IPageAttachmentUrlRetriever attachmentUrlRetriever)
        {
            this.propertiesRetriever = propertiesRetriever;
            this.siteService = siteService;
            this.attachmentUrlRetriever = attachmentUrlRetriever;
        }
 
 
        public ActionResult Index()
        {
            // Retrieves the GUID of the first selected attachment from the 'Attachments' property
            Guid guid = propertiesRetriever.Retrieve<CustomWidgetProperties>().Attachments.FirstOrDefault()?.FileGuid ?? Guid.Empty;
            // Retrieves the DocumentAttachment object that corresponds to the selected attachment GUID
            DocumentAttachment attachment = DocumentHelper.GetAttachment(guid, siteService.CurrentSite.SiteID);
 
            string url = String.Empty;
            if (attachment != null)
            {
                // Retrieves the relative URL of the selected attachment
                url = attachmentUrlRetriever.Retrieve(attachment).RelativePath;
            }
 
            // Custom logic...
 
            return View();
        }