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Trees

A guide to creating a custom tree in Umbraco

This section describes how to work with and create trees with Umbraco APIs.

Creating trees

To Create a Tree in a section of the Umbraco backoffice, you need to take several steps:

Create a TreeController class in C#. A new controller which inherits from the abstract Umbraco.Cms.Web.BackOffice.Trees.TreeController*` class and provides an implementation for two abstract methods:

GetTreeNodes (returns a TreeNodeCollection) - Responsible for rendering the content of the tree structure;
GetMenuForNode (returns a MenuItemCollection) - Responsible for returning the menu structure to use for a particular node within a tree.

You will need to add a constructor as TreeController requires this. See full code snippet in the "Implementing the Tree" section below.

The Tree attribute used to decorate the TreeController has multiple properties.

SectionAlias - Alias of the section in which the tree appears
TreeAlias - Alias of the tree
TreeTitle - The title of the tree
TreeGroup - The tree group, the tree belongs to
SortOrder - Sort order of the tree

For example:

[Tree("settings", "favouriteThingsAlias", TreeTitle = "Favourite Things Name", TreeGroup="favouritesGroup", SortOrder=5)]
public class FavouriteThingsTreeController : TreeController
{ }

The example above would register a custom tree with a title 'Favourite Things Name' in the Settings section of Umbraco, inside a custom group called 'Favourites'.

Tree Groups

Tree Groups enable you to group trees in a section. You provide the alias of the Tree Group name, you wish to add your tree to - see Constants.Trees.Groups for a list of existing group alias. An example of tree groups in the backoffice would be the Settings tree group and the Templating tree group in the Settings section.

If you add your own alias, you'll need to add a translation key. This can be done by adding a language file to a lang folder with your application folder in App_Plugins: App_Plugins/favouriteThings/lang/en-us.xml. This will avoid the alias appearing as the header in [square brackets].

The language file should contain the following XML:

<language>
  <area alias="treeHeaders">
    <key alias="favouritesGroup">Favourites</key>
  </area>
</language>

Customising the Root Tree Node

The first node in the tree is referred to as the Root Node. You can customise the Root Node by overriding the abstract CreateRootNode method. You can assign a custom icon to the Root Node. You can also specify a custom URL route path in the backoffice to use with your custom tree. The method can be useful if your section has a single node (single page app).

Implementing the Tree

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Umbraco.Cms.Core;
using Umbraco.Cms.Core.Actions;
using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Models.Trees;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Core.Trees;
using Umbraco.Cms.Web.BackOffice.Trees;
using Umbraco.Extensions;

namespace My.Website.Trees
{
    [Tree("settings", "favouriteThingsAlias", TreeTitle = "Favourite Things Name", TreeGroup = "favouritesGroup", SortOrder = 5)]
    public class FavouriteThingsTreeController : TreeController
    {

        private readonly IMenuItemCollectionFactory _menuItemCollectionFactory;

        public FavouriteThingsTreeController(ILocalizedTextService localizedTextService,
            UmbracoApiControllerTypeCollection umbracoApiControllerTypeCollection,
            IMenuItemCollectionFactory menuItemCollectionFactory,
            IEventAggregator eventAggregator)
            : base(localizedTextService, umbracoApiControllerTypeCollection, eventAggregator)
        {
            _menuItemCollectionFactory = menuItemCollectionFactory ?? throw new ArgumentNullException(nameof(menuItemCollectionFactory));
        }

        protected override ActionResult<TreeNodeCollection> GetTreeNodes(string id, FormCollection queryStrings)
        {
            var nodes = new TreeNodeCollection();

            // check if we're rendering the root node's children
            if (id == Constants.System.Root.ToInvariantString())
            {
                // you can get your custom nodes from anywhere, and they can represent anything...
                Dictionary<int, string> favouriteThings = new Dictionary<int, string>();
                favouriteThings.Add(1, "Raindrops on Roses");
                favouriteThings.Add(2, "Whiskers on Kittens");
                favouriteThings.Add(3, "Skys full of Stars");
                favouriteThings.Add(4, "Warm Woolen Mittens");
                favouriteThings.Add(5, "Cream coloured Unicorns");
                favouriteThings.Add(6, "Schnitzel with Noodles");

                // loop through our favourite things and create a tree item for each one
                foreach (var thing in favouriteThings)
                {
                    // add each node to the tree collection using the base CreateTreeNode method
                    // it has several overloads, using here unique Id of tree item,
                    // -1 is the Id of the parent node to create, eg the root of this tree is -1 by convention
                    // - the querystring collection passed into this route
                    // - the name of the tree node
                    // - css class of icon to display for the node
                    // - and whether the item has child nodes
                    var node = CreateTreeNode(thing.Key.ToString(), "-1", queryStrings, thing.Value, "icon-presentation", false);
                    nodes.Add(node);
                }
            }

            return nodes;
        }

        protected override ActionResult<MenuItemCollection> GetMenuForNode(string id, FormCollection queryStrings)
        {
            // create a Menu Item Collection to return so people can interact with the nodes in your tree
            var menu = _menuItemCollectionFactory.Create();

            if (id == Constants.System.Root.ToInvariantString())
            {
                // root actions, perhaps users can create new items in this tree, or perhaps it's not a content tree, it might be a read only tree, or each node item might represent something entirely different...
                // add your menu item actions or custom ActionMenuItems
                menu.Items.Add(new CreateChildEntity(LocalizedTextService));
                // add refresh menu item (note no dialog)
                menu.Items.Add(new RefreshNode(LocalizedTextService, true));
            }
            else
            {
                // add a delete action to each individual item
                menu.Items.Add<ActionDelete>(LocalizedTextService, true, opensDialog: true);
            }

            return menu;
        }

        protected override ActionResult<TreeNode?> CreateRootNode(FormCollection queryStrings)
        {
            var rootResult = base.CreateRootNode(queryStrings);
            if (!(rootResult.Result is null))
            {
                return rootResult;
            }

            var root = rootResult.Value;

            // set the icon
            root.Icon = "icon-hearts";
            // could be set to false for a custom tree with a single node.
            root.HasChildren = true;
            //url for menu
            root.MenuUrl = null;

            return root;
        }
    }
}

Responding to Tree Actions

The actions on items in an Umbraco Tree will trigger a request to load an AngularJS view, with a name corresponding to the name of the action, from a subfolder of the views folder matching the name of the 'customTreeAlias'.

Clicking on one of the 'Favourite Things' in the custom tree example will load an edit.html view from the folder: /views/favouriteThingsAlias/edit.html. The 'Delete' menu item would also load a view from: /views/favouriteThingsAlias/delete.html

When creating a custom tree as part of a Umbraco package, it is recommended to change the location of the default folder. It should be changed to the App_Plugins folder. You achieve this by decorating your MVC TreeController with the PluginController attribute.

@using Umbraco.Cms.Web.Common.Attributes;

[Tree("settings", "favouriteThingsAlias", TreeTitle = "Favourite Things Name")]
[PluginController("favouriteThings")]
public class FavouriteThingsTreeController : TreeController
{ }

The edit view in the example would now be loaded from the location: /App_Plugins/favouriteThings/backoffice/favouriteThingsAlias/edit.html

Providing functionality in your Tree Action Views

You can instruct the Umbraco backoffice to load additional JavaScript resources (eg. angularJS controllers) to use in conjunction with your 'tree action views' by adding a package.manifest file in the same folder location as your views.

For example...

{
    "javascript": [
        "~/App_Plugins/favouriteThings/favouriteThings.resource.js",
        "~/App_Plugins/favouriteThings/backoffice/favouriteThingsAlias/edit.controller.js",
        "~/App_Plugins/favouriteThings/backoffice/favouriteThingsAlias/delete.controller.js"
    ]
}

...this manifest would load files for two controllers to work with the edit and delete views and a general resource file, perhaps containing code to retrieve, create, edit and delete 'favourite things' from some external non-Umbraco API.

Our Tree Action View would then be wired to the loaded controller using the ng-controller attribute. The delete view would perhaps the delete view look a little bit like this:

<div class="umb-dialog umb-pane" ng-controller="Our.Umbraco.FavouriteThings.DeleteController">
    <div class="umb-dialog-body">
        <p class="umb-abstract">
            Are you sure you want to delete this favourite thing: <strong>{{currentNode.name}}</strong> ?
        </p>
        <umb-confirm on-confirm="performDelete" on-cancel="cancel">
        </umb-confirm>
    </div>
</div>

see Tree Actions for a list of tree ActionMenuItems and IActions

Single Node Trees / Customising the Root Node Action

It is possible to create 'trees' consisting of only a single node - perhaps to provide an area to control some settings or a placeholder for a single page backoffice app. See the LogViewer in the settings section for a good example. (or as in the case of the 'settings/content templates' tree, it's possible to have a custom view for the root node as an 'introduction' page to the tree).

In both scenarios you need to override the CreateRootNode method for the custom tree.

[Tree("settings", "favouritistThingsAlias", TreeTitle = "Favourite Thing", TreeGroup = "favoritesGroup", SortOrder = 5)]
[PluginController("favouriteThing")]
public class FavouritistThingsTreeController : TreeController
{ }

You can override the CreateRootNode method to set the 'RoutePath' to where the single page application will live (or introduction page). Setting HasChildren to false will result in a Single Node Tree.

protected override ActionResult<TreeNode> CreateRootNode(FormCollection queryStrings)
{
    var rootResult = base.CreateRootNode(queryStrings);
    if (!(rootResult.Result is null))
    {
        return rootResult;
    }

    var root = rootResult.Value;

    //optionally setting a routepath would allow you to load in a custom UI instead of the usual behaviour for a tree
    root.RoutePath = string.Format("{0}/{1}/{2}", Constants.Applications.Settings, "favouritistThingsAlias", "overview");
    // set the icon
    root.Icon = "icon-hearts";
    // set to false for a custom tree with a single node.
    root.HasChildren = false;
    //url for menu
    root.MenuUrl = null;

    return root;
}

The RoutePath should be in the format of: section/treeAlias/method. As our example controller uses the PluginController attribute, clicking the root node would now request /App_Plugins/favouriteThing/backoffice/favouritistThingsAlias/overview.html. If you are not using the PluginController attribute, then the request would be to /umbraco/views/favouritistThingsAlias/overview.html.

Full Width App - IsSingleNodeTree

It's possible to make your single node tree app stretch across the full screen of the backoffice (no navigation tree) - see Packages section for an example. To achieve this add an additional attribute IsSingleNodeTree, in the Tree attribute for the custom controller.

[Tree("settings", "favouritistThingsAlias", IsSingleNodeTree = true, TreeTitle = "Favourite Thing", TreeGroup = "favoritesGroup", SortOrder = 5)]
[PluginController("favouriteThing")]
public class FavouritistThingsTreeController : TreeController
{ }

Tree notifications

All tree notications are defined in the namespace Umbraco.Cms.Core.Notifications.

For more information about registering and using notifications see Notifications

RootNodeRenderingNotification

The RootNodeRenderingNotification is published whenever a tree's root node is created.

Members:

TreeNode Node
FormCollection QueryString
string TreeAlias

Usage:

public void Handle(RootNodeRenderingNotification notification)
{
    // normally you will want to target a specific tree, this can be done by checking the tree alias
    if (notification.TreeAlias.Equals("content"))
    {
        notification.Node.Name = "My new title";
    }
}

TreeNodesRenderingNotification

The TreeNodesRenderingNotification is published whenever a list of child nodes are created.

Members:

TreeNodeCollection Nodes
FormCollection QueryString
string TreeAlias

Usage:

using Umbraco.Cms.Core.Security;

public class TreeNotificationHandler :INotificationHandler<TreeNodesRenderingNotification>
{
    private readonly IBackOfficeSecurityAccessor _backOfficeSecurityAccessor;

    public TreeNotificationHandler(IBackOfficeSecurityAccessor backOfficeSecurityAccessor)
    {
        _backOfficeSecurityAccessor = backOfficeSecurityAccessor;
    }

    public void Handle(TreeNodesRenderingNotification notification)
    {
        // this example will filter any content tree node whose node name starts with
        // 'Private', for any user that is in the customUserGroup
        if (notification.TreeAlias.Equals("content") &&
            _backOfficeSecurityAccessor.BackOfficeSecurity.CurrentUser.Groups.Any(f =>
                f.Alias.Equals("customUserGroupAlias")))
        {
            notification.Nodes.RemoveAll(node => node.Name.StartsWith("Private"));
        }
    }
}

MenuRenderingNotification

The MenuRenderingNotification is raised whenever a menu is generated for a tree node.

Members:

MenuItemCollection Menu
string NodeId
FormCollection QueryString
string TreeAlias

Usage:

using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Notifications;
using Umbraco.Cms.Core.Security;

public class TreeNotificationHandler : INotificationHandler<MenuRenderingNotification>
{
    private readonly IBackOfficeSecurityAccessor _backOfficeSecurityAccessor;

    public TreeNotificationHandler(IBackOfficeSecurityAccessor backOfficeSecurityAccessor)
    {
        _backOfficeSecurityAccessor = backOfficeSecurityAccessor;
    }

    public void Handle(MenuRenderingNotification notification)
    {
        // this example will add a custom menu item for all admin users

        // for all content tree nodes
        if (notification.TreeAlias.Equals("content") &&
            _backOfficeSecurityAccessor.BackOfficeSecurity.CurrentUser.Groups.Any(x =>
                x.Alias.InvariantEquals("admin")))
        {
            // Creates a menu action that will open /umbraco/currentSection/itemAlias.html
            var menuItem = new Umbraco.Cms.Core.Models.Trees.MenuItem("itemAlias", "Item name");

            // optional, if you don't want to follow the naming conventions, but do want to use a angular view
            // you can also use a direct path "../App_Plugins/my/long/url/to/view.html"
            menuItem.AdditionalData.Add("actionView", "my/long/url/to/view.html");

            // sets the icon to icon-wine-glass
            menuItem.Icon = "wine-glass";
            // insert at index 5
            notification.Menu.Items.Insert(5, menuItem);
        }
    }
}

Tree Actions and User Permissions

See a list of Tree Actions and User Permission Codes

Tree Actions

A guide to creating a custom tree action in Umbraco

Items in an Umbraco Tree can have associated Actions. The actions visible to the currently logged in user can be controlled via User Permissions.

You can set a User's permissions for each item in the Umbraco Content tree from the User Section of the Umbraco Backoffice.

If you are developing a custom section, or a custom Dashboard, you might want to display some different options based on a User's permission set on a particular item.

For example, on a custom dashboard you might add a quick 'Create a Blog Post' button for an editor, but only if that editor has permissions to create a blog post. You could create some sort of API endpoint, to call from your AngularJS controller, that in turn uses the UserService to return the current user's permissions. Then you can see whether they have the required permission to 'create' within the site's blog section.

But how to know which letter corresponds to which Tree Action?

Each tree action in Umbraco implements the IAction interface, and each Action has a corresponding 'Letter', and a boolean value describing whether permissions can be assigned for an action.

When you pull back the AssignedPermissions for a user on a particular item, it is these letters that indicate which actions the User is permitted to perform in the context of the tree item.

User Permission Codes

Here is a list of the tree actions and associated user permission codes shipped by Umbraco CMS and add-on projects (such as Umbraco Deploy), as well as those used by some community packages.

If building a package or adding custom tree actions to your solution, it's important to pick a permission letter that doesn't clash with one of these.

Note: up until Umbraco Deploy 9.2.0, the letter "N" was used for the "Queue For Transfer" action. In 9.2.1 it was changed to be "T", to avoid clashing with the letter selected for the Umbraco CMS "Notify" action, introduced in CMS version 8.18.

Trees

A guide to creating a custom tree in Umbraco

This section describes how to work with and create trees with Umbraco APIs.

Creating trees

To Create a Tree in a section of the Umbraco backoffice, you need to take several steps:

GetTreeNodes (returns a TreeNodeCollection) - Responsible for rendering the content of the tree structure;
GetMenuForNode (returns a MenuItemCollection) - Responsible for returning the menu structure to use for a particular node within a tree.

You will need to add a constructor as TreeController requires this. See full code snippet in the "Implementing the Tree" section below.

The Tree attribute used to decorate the TreeController has multiple properties.

SectionAlias - Alias of the section in which the tree appears
TreeAlias - Alias of the tree
TreeTitle - The title of the tree
TreeGroup - The tree group, the tree belongs to
SortOrder - Sort order of the tree

For example:

[Tree("settings", "favouriteThingsAlias", TreeTitle = "Favourite Things Name", TreeGroup="favouritesGroup", SortOrder=5)]
public class FavouriteThingsTreeController : TreeController
{ }

The example above would register a custom tree with a title 'Favourite Things Name' in the Settings section of Umbraco, inside a custom group called 'Favourites'.

Tree Groups

The language file should contain the following XML:

<language>
  <area alias="treeHeaders">
    <key alias="favouritesGroup">Favourites</key>
  </area>
</language>

Customising the Root Tree Node

Implementing the Tree

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Umbraco.Cms.Core;
using Umbraco.Cms.Core.Actions;
using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Models.Trees;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Core.Trees;
using Umbraco.Cms.Web.BackOffice.Trees;
using Umbraco.Extensions;

namespace My.Website.Trees
{
    [Tree("settings", "favouriteThingsAlias", TreeTitle = "Favourite Things Name", TreeGroup = "favouritesGroup", SortOrder = 5)]
    public class FavouriteThingsTreeController : TreeController
    {

        private readonly IMenuItemCollectionFactory _menuItemCollectionFactory;

        public FavouriteThingsTreeController(ILocalizedTextService localizedTextService,
            UmbracoApiControllerTypeCollection umbracoApiControllerTypeCollection,
            IMenuItemCollectionFactory menuItemCollectionFactory,
            IEventAggregator eventAggregator)
            : base(localizedTextService, umbracoApiControllerTypeCollection, eventAggregator)
        {
            _menuItemCollectionFactory = menuItemCollectionFactory ?? throw new ArgumentNullException(nameof(menuItemCollectionFactory));
        }

        protected override ActionResult<TreeNodeCollection> GetTreeNodes(string id, FormCollection queryStrings)
        {
            var nodes = new TreeNodeCollection();

            // check if we're rendering the root node's children
            if (id == Constants.System.Root.ToInvariantString())
            {
                // you can get your custom nodes from anywhere, and they can represent anything...
                Dictionary<int, string> favouriteThings = new Dictionary<int, string>();
                favouriteThings.Add(1, "Raindrops on Roses");
                favouriteThings.Add(2, "Whiskers on Kittens");
                favouriteThings.Add(3, "Skys full of Stars");
                favouriteThings.Add(4, "Warm Woolen Mittens");
                favouriteThings.Add(5, "Cream coloured Unicorns");
                favouriteThings.Add(6, "Schnitzel with Noodles");

                // loop through our favourite things and create a tree item for each one
                foreach (var thing in favouriteThings)
                {
                    // add each node to the tree collection using the base CreateTreeNode method
                    // it has several overloads, using here unique Id of tree item,
                    // -1 is the Id of the parent node to create, eg the root of this tree is -1 by convention
                    // - the querystring collection passed into this route
                    // - the name of the tree node
                    // - css class of icon to display for the node
                    // - and whether the item has child nodes
                    var node = CreateTreeNode(thing.Key.ToString(), "-1", queryStrings, thing.Value, "icon-presentation", false);
                    nodes.Add(node);
                }
            }

            return nodes;
        }

        protected override ActionResult<MenuItemCollection> GetMenuForNode(string id, FormCollection queryStrings)
        {
            // create a Menu Item Collection to return so people can interact with the nodes in your tree
            var menu = _menuItemCollectionFactory.Create();

            if (id == Constants.System.Root.ToInvariantString())
            {
                // root actions, perhaps users can create new items in this tree, or perhaps it's not a content tree, it might be a read only tree, or each node item might represent something entirely different...
                // add your menu item actions or custom ActionMenuItems
                menu.Items.Add(new CreateChildEntity(LocalizedTextService));
                // add refresh menu item (note no dialog)
                menu.Items.Add(new RefreshNode(LocalizedTextService, true));
            }
            else
            {
                // add a delete action to each individual item
                menu.Items.Add<ActionDelete>(LocalizedTextService, true, opensDialog: true);
            }

            return menu;
        }

        protected override ActionResult<TreeNode?> CreateRootNode(FormCollection queryStrings)
        {
            var rootResult = base.CreateRootNode(queryStrings);
            if (!(rootResult.Result is null))
            {
                return rootResult;
            }

            var root = rootResult.Value;

            // set the icon
            root.Icon = "icon-hearts";
            // could be set to false for a custom tree with a single node.
            root.HasChildren = true;
            //url for menu
            root.MenuUrl = null;

            return root;
        }
    }
}

Responding to Tree Actions

@using Umbraco.Cms.Web.Common.Attributes;

[Tree("settings", "favouriteThingsAlias", TreeTitle = "Favourite Things Name")]
[PluginController("favouriteThings")]
public class FavouriteThingsTreeController : TreeController
{ }

The edit view in the example would now be loaded from the location: /App_Plugins/favouriteThings/backoffice/favouriteThingsAlias/edit.html

Providing functionality in your Tree Action Views

For example...

{
    "javascript": [
        "~/App_Plugins/favouriteThings/favouriteThings.resource.js",
        "~/App_Plugins/favouriteThings/backoffice/favouriteThingsAlias/edit.controller.js",
        "~/App_Plugins/favouriteThings/backoffice/favouriteThingsAlias/delete.controller.js"
    ]
}

Our Tree Action View would then be wired to the loaded controller using the ng-controller attribute. The delete view would perhaps the delete view look a little bit like this:

<div class="umb-dialog umb-pane" ng-controller="Our.Umbraco.FavouriteThings.DeleteController">
    <div class="umb-dialog-body">
        <p class="umb-abstract">
            Are you sure you want to delete this favourite thing: <strong>{{currentNode.name}}</strong> ?
        </p>
        <umb-confirm on-confirm="performDelete" on-cancel="cancel">
        </umb-confirm>
    </div>
</div>

see Tree Actions for a list of tree ActionMenuItems and IActions

Single Node Trees / Customising the Root Node Action

In both scenarios you need to override the CreateRootNode method for the custom tree.

[Tree("settings", "favouritistThingsAlias", TreeTitle = "Favourite Thing", TreeGroup = "favoritesGroup", SortOrder = 5)]
[PluginController("favouriteThing")]
public class FavouritistThingsTreeController : TreeController
{ }

protected override ActionResult<TreeNode> CreateRootNode(FormCollection queryStrings)
{
    var rootResult = base.CreateRootNode(queryStrings);
    if (!(rootResult.Result is null))
    {
        return rootResult;
    }

    var root = rootResult.Value;

    //optionally setting a routepath would allow you to load in a custom UI instead of the usual behaviour for a tree
    root.RoutePath = string.Format("{0}/{1}/{2}", Constants.Applications.Settings, "favouritistThingsAlias", "overview");
    // set the icon
    root.Icon = "icon-hearts";
    // set to false for a custom tree with a single node.
    root.HasChildren = false;
    //url for menu
    root.MenuUrl = null;

    return root;
}

Full Width App - IsSingleNodeTree

[Tree("settings", "favouritistThingsAlias", IsSingleNodeTree = true, TreeTitle = "Favourite Thing", TreeGroup = "favoritesGroup", SortOrder = 5)]
[PluginController("favouriteThing")]
public class FavouritistThingsTreeController : TreeController
{ }

Tree notifications

All tree notications are defined in the namespace Umbraco.Cms.Core.Notifications.

For more information about registering and using notifications see Notifications

RootNodeRenderingNotification

The RootNodeRenderingNotification is published whenever a tree's root node is created.

Members:

TreeNode Node
FormCollection QueryString
string TreeAlias

Usage:

public void Handle(RootNodeRenderingNotification notification)
{
    // normally you will want to target a specific tree, this can be done by checking the tree alias
    if (notification.TreeAlias.Equals("content"))
    {
        notification.Node.Name = "My new title";
    }
}

TreeNodesRenderingNotification

The TreeNodesRenderingNotification is published whenever a list of child nodes are created.

Members:

TreeNodeCollection Nodes
FormCollection QueryString
string TreeAlias

Usage:

using Umbraco.Cms.Core.Security;

public class TreeNotificationHandler :INotificationHandler<TreeNodesRenderingNotification>
{
    private readonly IBackOfficeSecurityAccessor _backOfficeSecurityAccessor;

    public TreeNotificationHandler(IBackOfficeSecurityAccessor backOfficeSecurityAccessor)
    {
        _backOfficeSecurityAccessor = backOfficeSecurityAccessor;
    }

    public void Handle(TreeNodesRenderingNotification notification)
    {
        // this example will filter any content tree node whose node name starts with
        // 'Private', for any user that is in the customUserGroup
        if (notification.TreeAlias.Equals("content") &&
            _backOfficeSecurityAccessor.BackOfficeSecurity.CurrentUser.Groups.Any(f =>
                f.Alias.Equals("customUserGroupAlias")))
        {
            notification.Nodes.RemoveAll(node => node.Name.StartsWith("Private"));
        }
    }
}

MenuRenderingNotification

The MenuRenderingNotification is raised whenever a menu is generated for a tree node.

Members:

MenuItemCollection Menu
string NodeId
FormCollection QueryString
string TreeAlias

Usage:

using Umbraco.Cms.Core.Events;
using Umbraco.Cms.Core.Notifications;
using Umbraco.Cms.Core.Security;

public class TreeNotificationHandler : INotificationHandler<MenuRenderingNotification>
{
    private readonly IBackOfficeSecurityAccessor _backOfficeSecurityAccessor;

    public TreeNotificationHandler(IBackOfficeSecurityAccessor backOfficeSecurityAccessor)
    {
        _backOfficeSecurityAccessor = backOfficeSecurityAccessor;
    }

    public void Handle(MenuRenderingNotification notification)
    {
        // this example will add a custom menu item for all admin users

        // for all content tree nodes
        if (notification.TreeAlias.Equals("content") &&
            _backOfficeSecurityAccessor.BackOfficeSecurity.CurrentUser.Groups.Any(x =>
                x.Alias.InvariantEquals("admin")))
        {
            // Creates a menu action that will open /umbraco/currentSection/itemAlias.html
            var menuItem = new Umbraco.Cms.Core.Models.Trees.MenuItem("itemAlias", "Item name");

            // optional, if you don't want to follow the naming conventions, but do want to use a angular view
            // you can also use a direct path "../App_Plugins/my/long/url/to/view.html"
            menuItem.AdditionalData.Add("actionView", "my/long/url/to/view.html");

            // sets the icon to icon-wine-glass
            menuItem.Icon = "wine-glass";
            // insert at index 5
            notification.Menu.Items.Insert(5, menuItem);
        }
    }
}

Tree Actions and User Permissions

See a list of Tree Actions and User Permission Codes