SPRadGrid supports the native SharePoint field types, however, the Q3 release version is the first to sport the possibility of binding the grid to custom field types. As a consequence this will give you the chance to binding the grid to your own content types. The only requirement to keep when developing the custom field type is to specify a display mode template and not just a default one.

In the example below, SongName is a custom field type which is connected to a Song list. The field rendering control features a RadComboBox in edit mode that retrieves the names of all songs in the Song list.
 

 Favorite Songs

 
Drag a column header and drop it here to group by that column
Song NamePerformer
Fifteen Tulips Mimi Ivanova
Maybe Signal
Clovers Lili Ivanova
Chrysanthema Lili Ivanova
Cricket Lili Ivanova
The Old Green Fountain Mimi Ivanova
  • Sort Ascending
  • Sort Descending
  • Clear Sorting
  • Group By
  • Ungroup
  • Columns
  • Filter
    • select
      select