Hi Vinamra,
When you enhance the view by default CTXT class also will be enhanced, when you enhance the context node then only system will create corresponding method create_"context node name" in your Z_CTXT class.
Did you check Z_CTXT class for the create_ibase method, This class should have added this method with code like this
model = owner->create_model(
class_name = 'ZCLICCMP_IB_IBTREERESULTL_CN00' "cl_crm_ic_ibase_constants=>gc_ibtree_firstlevel_class "#EC NOTEXT
model_id = cl_crm_ic_ibase_constants=>gc_ibtree_node_name ). "#EC NOTEXT
ibasetree ?= model.
Best Regards,
Dharmakasi.