Select TreeView Checkboxes (Multiple levels)

I've managed to populate the TreeView to a Node Depth of 4. I folloewd the official MSDN example (This is the first time I've ever used this control). Users will select and save multiple Companies, Divisions and Departments (Code I must still try to write). What I'm trying to do now is display the selected Areas in the TreeView when the Page loads so users can see their persisted changes.
protected void PopulateNode(Object sender, TreeNodeEventArgs e) { // Call the appropriate method to populate a node at a particular level. switch (e.Node.Depth) { case 0:// Company PopulateCompany(e.Node);//1 break; case 1:// Division PopulateDivision(e.Node);//2 break; case 2:// Department PopulateDepartment(e.Node);//3 break; } } What I'm trying to do now, is programat ...