This example demonstrates how to control which rows or cells to be read only.
See also:
WPF: http://docs.telerik.com/devtools/wpf/controls/radgridview/columns/how-to/read-only-rows-cells.html
SL: http://docs.telerik.com/devtools/silverlight/controls/radgridview/columns/how-to/read-only-rows-cells.html