asp.net page with async asp.net tree control with check boxes.

asp.net page with asp.net tree control with check boxes. The project is for asp.net page with tree control, dropdown and button. Tree control. Control will have icon, checkbox and title per each item. Checkbox won't have POSTBACK event. Check box might be disabled or enabled. Tree control will be data-bound. Data sources will be per level. There might be upto 10 levels. The control should render as the data source gets available, which means asynchronously. E.g. there might be 100 items on 2nd level, and 10000 items on each of the items on the 3rd level. The control will render branch by branch, level by level. No psotbacks. While waiting for the data get ready, waiting animation should show. The data source per level can be a list or structure, I'm open to whatever works better for you. There will be dropdown with Keys and Apply button. The user will select set of checkboxes and click Apply. That will result in list of checkbox values stored per Key value. When user selects another Key in the dropdown, the Tree control should expand to show all selected items and up the tree. Tree down from selected item will be collapsed. OnLoad event without any Key selected in the dropdown will result in the whole Tree shown collapsed. Validation: If user selects an item (checkbox) all checkboxes up and down the tree should be de-selected. Only 0 or 1 checkbox on the branch can be selected. No POSTBACK allowed on checkbox