For example, a student can register a class. The class node has a date field indicating whether the class is active for registering. The registration node has an entityreference field referencing to the class node. I get the referencing class nodes by using "Views: Filter by an entity reference view" option. This view has a filter of "current date is between the start and the end date". Now, if the count of the reference view result rows is 0, the student should be redirected from the node/add/registration page to an explanation page which tells students there is currently no active classes for registering. On the module entityreference_count page, it says,
Currently this module only works with entityreference fields configured to use the "Simple (with optional filter by bundle)" option. It does not work with the "Views: Filter by an entity reference view" option. This may be addressed in a future release.
How can I make it?