c# - Is this a Liskov Substitution Principle violation? -



c# - Is this a Liskov Substitution Principle violation? -

my custom button button, violating lsp?

class conditionalbutton : button { protected override void onclick(eventargs e) { if (condition()) base.onclick(e); } private bool condition() { //return true or false } }

in sentiment does violate lsp. please refer object mentor simplified definition of liskov substitution principle object mentor article:

“functions utilize pointers or references base of operations classes must able utilize objects of derived classes without knowing it.”

it seem ok can utilize conditionalbutton button point of view. but:

in order lsp hold, , open-closed principle, derivatives must conform behavior clients expect of base of operations classes use

and sure clients expect after clicking button, onclick executed.

moreover, same article:

...when redefining routine [in derivative], may replace precondition weaker one, , postcondition stronger one.

in opinion, conditionalbutton violates lsp in current form, because condition allows click button, while logic related button won't executed. if condition related enabled/disabled flag - not violate lsp.

c# oop solid-principles

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