DataModel must implement org.primefaces.model.SelectableDataModel when selection is enabled, but I have already defined rowKey

Question

I've a selectable PrimeFaces 3.4.1 datatable:

<p:dataTable value="#{projectAdminisrationMB.selectedUserMemberOfGroups}" var="group1" 
    rowKey="#{group1.name}" selectionMode="single" selection="#{projectAdminisrationMB.selectedBelongToGroup}">
    ...
</p:dataTable>

I'm getting this error:

com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback visit Grave: javax.faces.FacesException: DataModel must implement org.primefaces.model.SelectableDataModel when selection is enabled.

But I have already set rowKey as per FacesException: DataModel must implement org.primefaces.model.SelectableDataModel when selection is enabled. How is this caused and how can I solve it?

Answer 1

This can occur when the EL expression in the rowKey attribute ever evaluates null.

Make sure that the name property of your Group instance is never null. Otherwise better use a property representing the autogenerated DB primary key, such as #{group1.id} — if you have one.