Table - Table-Tree

[Koreets61]

Please help with a component, I recently started learning C#
I have a data set:

{
    "a": "b",
    "c": [
        {"c1": "d1"}, 
        {"c2": "d2"}
   ]
}

I want to use the Table-Tree component, but I can't figure out how to properly describe the TreeNodeConverter and OnTreeExpand functions. I don't even have an idea of ​​what to give as an example.

I want to see the data "c" in the drop down list