What is the test for sustaining an action on appeal against a finding of improper reasoning?

"The rule is thus stated in Davey v. Southern Pac. Co. (1897) 116 C. 325, 329, 48 P. 117: 'The fact that the action of the court may have been based upon an erroneous theory of the case, or upon an improper or unsound course of reasoning, cannot determine the question of its propriety. No rule of decision is better or more firmly established by authority, nor one resting upon a sounder basis of reason and propriety, than that a ruling or decision, itself correct in law, will not be disturbed on appeal merely because given for a wrong reason. If right upon any theory of the law applicable to the case, it must be sustained regardless of the considerations which may have moved the trial court to its conclusion.' "