Hello Angie,

You can try subscribing to the NodeDataBound event of the EmbeddedTree where you can access the data for each item and decide which properties to set:

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        RadDropDownTree1.DataFieldID = "ID";
        RadDropDownTree1.DataFieldParentID = "ParentID";
        RadDropDownTree1.DataValueField = "Value";
        RadDropDownTree1.DataTextField = "Text";
        RadDropDownTree1.EmbeddedTree.NodeDataBound += EmbeddedTree_NodeDataBound;
        RadDropDownTree1.DataSource = GetData();
        RadDropDownTree1.DataBind();
    }
}

private void EmbeddedTree_NodeDataBound(object sender, RadTreeNodeEventArgs e)
{
     // decide which Node properties to set
}

Regards,
Peter Milchev
Progress Telerik

Hi Peter, thank you for the reply.  I also found your reply in this link: https://www.telerik.com/forums/hide-disable-node.

In your above example, the right side of RadDropDownTree1.EmbeddedTree.NodeDataBound += EmbeddedTree_NodeDataBound does not resolve for me. See attached image.

So instead, I tried using the available events from https://docs.telerik.com/devtools/aspnet-ajax/controls/treeview/server-side-programming/events/nodedatabound, but the "enabled" property is not available.  I tried using the "checkable" property instead, even though I am not using checkboxes.

It does prevent the item from being selected, however the client events OnClientEntryAdded and OnClientEntryAdding still fire.  I would expect the OnClientEntryAdded not to be fired, since it's not being added to the entries.

In order to handle the client event firing, I would need to know how to detect if the node is disabled in javascript.

Thank you!

Hello Angie,

Once you add the RadDropDownTree1.EmbeddedTree.NodeDataBound += EmbeddedTree_NodeDataBound, you need to have a method with the same name and the correct arguments:

private void EmbeddedTree_NodeDataBound(object sender, Telerik.Web.UI.RadTreeNodeEventArgs e)
{
    // use data item data instead
    if (e.Node.Text == "World Continents")
    {
        e.Node.Enabled = false;
    }
}

Also, you can add use Visual Studio to generate the handler for you by typing  RadDropDownTree1.EmbeddedTree.NodeDataBound += and then press the TAB key twice.

The link that you have shared is actually showing the TreeView control's events, but the snippet below it is actually the one for the DropDownTree, not the TreeView:

protected void ddtForums_NodeDataBound(object sender, DropDownTreeNodeDataBoundEventArguments e)

The DropDownTreeNode, unfortunately, does not have all the properties of the TreeView's RadTreeNode. That is why the TreeView's NodeDataBound is needed. 

Regarding the Checkable property, it controls the checkbox of the node when the checkboxes are enabled for the DropDownTree. If you want to control if the node can be selected, you need to use the Enabled property of the TreeView node, not the DropDownTree's:

• https://docs.telerik.com/devtools/aspnet-ajax/api/server/Telerik.Web.UI/RadTreeNode#enabled 

Once the TreeView's node is disabled, it will not be selectable. 

Regards,
Peter Milchev
Progress Telerik