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using umbraco.controls.Tree;
using umbraco.editorControls.MultiNodeTreePicker;

namespace Orc.example.plugin.dialogs.TreeExample
{
    public class ExampleContentTree : FilteredContentTree
    {
        public ExampleContentTree(string app) : base(app) { }
        public override int StartNodeID
        {
            get { return 1077; }
        }
    }
    public class ExampleContentTreeControl : CustomTreeControl
    {
        public ExampleContentTreeControl()
        {
            ShowContextMenu = false;
            Height = 300;
            TreeType = typeof (ExampleContentTree).Name;
            FunctionToCall = "onNodeSelected";
        }
    }
}

using System.Linq;
using Umbraco.Core;
using Umbraco.Web;
using umbraco.cms.presentation.Trees;

namespace Orc.example.plugin.dialogs.TreeExample
{
    public class CustomTreeExampleInitializer : IApplicationEventHandler
    {
        public void OnApplicationInitialized(UmbracoApplication app, ApplicationContext ctx)
        {
            // get a handle on the main content tree
            var contentTree = TreeDefinitionCollection.Instance.Single(x => x.Tree.Alias.ToUpper() == "CONTENT");

            // create our tree type
            var filteredTreeType = typeof (ExampleContentTree);

            // make the definition
            var filteredContentTreeDefinition = new TreeDefinition(filteredTreeType,
                                                         new umbraco.BusinessLogic.ApplicationTree(true, false, 0, contentTree.Tree.ApplicationAlias, filteredTreeType.Name, null, null, null, null, null, null),
                                                         contentTree.App);
            // add it to the collection
            TreeDefinitionCollection.Instance.Add(filteredContentTreeDefinition);
        }

        public void OnApplicationStarting(UmbracoApplication httpApplication, ApplicationContext applicationContext)
        {
        }

        public void OnApplicationStarted(UmbracoApplication httpApplication, ApplicationContext applicationContext)
        {
        }
    }
}

using System;
using Orc.example.plugin.dialogs.TreeExample;

namespace Orc.example.plugin.dialogs
{
    public partial class CustomTreeExample : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                TreeContainer.Controls.Add(new ExampleContentTreeControl());
            }
        }

        // once the user has selected their node, they click ok and this method is fired
        protected void DisplaySelectedNodeId(object sender, EventArgs e)
        {

            // here we'll just output the selected node id as text;
            var selectedNodeId = SelectedNode.Value;

            // ... do stuff with selected node id ...

            // for our example, update the UI and show the selected node id
            TreeAndButtons.Visible = false;
            Results.Visible = true;
            resultsText.Text = selectedNodeId;

        }
    }
}

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CustomTreeExample.aspx.cs"
    Inherits="Orc.example.plugin.dialogs.CustomTreeExample" MasterPageFile="/umbraco/masterpages/umbracoDialog.Master" %>

<%@ Register TagPrefix="cc1" Namespace="umbraco.uicontrols" Assembly="controls" %>
<%@ Register TagPrefix="treepicker" Namespace="umbraco.uicontrols.TreePicker" Assembly="controls" %>
<%@ Register TagPrefix="umbraco" TagName="TreeControl" Src="~/umbraco/controls/Tree/TreeControl.ascx" %>

<asp:Content ContentPlaceHolderID="body" runat="server">
    
    <script type="text/javascript">
        function onNodeSelected(id)
        {
            document.getElementById("<%= SelectedNode.ClientID %>").value = id;
        }
    </script>
    <% // here we add a hidden field to store the nodeID in during postback %>
    <asp:HiddenField ID="SelectedNode" runat="server" />
    <% // here we create a very simple ui container %>
    <asp:Panel runat="server" ID="TreeAndButtons">
        <% // we create a pane to hold the tree %>
        <cc1:Pane runat="server" Visible="true">
            <% // add our usual umbraco ui classes %>
            <div style="padding-top: 10px;" class="guiDialogNormal">
                <% // here we actually want to render the tree (the tree is injected into the PropertyPanel as a Child Control) %>
                <cc1:PropertyPanel ID="TreeContainer" runat="server" Style="overflow: auto; height: 220px;position: relative;">
                </cc1:PropertyPanel>
            </div>
        </cc1:Pane>
        <% // now lets help our users with some basic ui commands%>
        <p> Pick a node and click ok!

            <% // user will select their node, and then click ok %>
            <asp:Button ID="OkButton" runat="server" Text="ok" OnClick="DisplaySelectedNodeId" />
            <em>or</em>
            <% // create a cancel button %>
            <a href="#" onclick="UmbClientMgr.closeModalWindow()">Cancel</a>
        </p>
    </asp:Panel>
    <asp:Panel runat="server" ID="Results" Visible="False">
        Do stuff with node : <asp:Literal runat="server" ID="resultsText"></asp:Literal>
    </asp:Panel>
</asp:Content>