Adds the passed in entity field instance to the list. entity fields can be added just once. If the field is already in the collection, the index of the field in the list is returned.

public int Add<TEntityField>(
	TEntityField fieldToAdd
)
where TEntityField : IEntityFieldCore

Public Function Add(Of TEntityField As IEntityFieldCore) ( 
	fieldToAdd As TEntityField
) As Integer