Set image for rad tree node depending on its attribute using css

[Vitalii]

Hello Telerik!

I have my RadTreeView:

<telerik:RadTreeView runat="server" ID="TreeViewUnit"  CssClass="TreeView"
           ShowLineImages="False" Skin="Forest"
    OnDataBound="TreeViewUnit_DataBound"
    OnNodeClick="TreeViewUnit_NodeClick"
           meta:resourcekey="TreeViewUnitResource1">

And I have binding in code behind where I set two attributes:

item.Attributes["Item"] = "Unit";

or

item.Attributes["Item"] = "Respondent";

Also I set node images in code behind and it's bad.

item.ImageUrl = imageFolder + "folder-icon.png";
node.ImageUrl = imageFolder + "profile_icon.png";

So I want to do it right way in order to reduce traffic and use CSS for node image.
I tried:

.RadTreeView .rtImg {
    background-image: url("/Styles/images/plusminus_icon.png") !important;
}
.RadTreeView_Forest .rtImg {
    background-image: url("/Styles/images/profile_icon.png") !important;
}

but it does not work.

For example:

.RadTreeView_Forest .rtPlus, .RadTreeView_Forest .rtMinus {
    background-image: url("/Styles/images/plusminus_icon.png") !important;
}

works perfectly fine for minus sign images.


Any ideas how can I do it? And It will be great if there was a way to select image depending on node attribute. I think I can manage to do it using javascript and DOM elements, but adding images using CSS still a question.
Thanks)

[Vitalii]

Still interesting, any ideas how can it be done via client side?