Items layer is the easiest way to display items over a map. The C1ItemsLayer class represents an items layer. It can be added to the maps in the similar manner, as a vector layer or a virtual layer using the C1Layer Collection Editor, in source view or in code. 

In the factories example used in the topic Add Items Layer, we add an items layer over the maps control:

<c1:C1ItemsLayer Request="requestOffices" />

In this sample the items layer uses its Request property, to call the client side function to display offices over the maps control.