What is the test for estoppel in law?

In Hulowski v. Hulowski, supra, in determining whether the facts amounted to an estoppel in law Mr. Justice McNiven at p. 147 referred with approval to that which was stated in Greenwood v. Martins Bank in A.C. p. 57 and in L.J.K.B. at p. 626: "The essential factors giving rise to an estoppel are I think: (1) A representation or conduct amounting to a representation intended to induce a course of conduct on the part of the person to whom the representation is made. (2) An act or omission resulting from the representation, whether actual or by conduct, by the person to whom the representation was made. (3) Detriment to such person as a consequence of the act or omission. Mere silence cannot amount to a representation, but, when there is a duty to disclose, deliberate silence may become significant and amount to a representation."