Meaning of shàng mén:
上门
to drop in; to visit; to lock a door; (of a shop) to close; to go and live with one's wife's family, in effect becoming a member of her family
Nǐ kěyǐ suíshí shàngmén bàifǎng wǒmen.
你可以随时上门拜访我们。
You can drop in and visit us anytime.
Tā míngtiān huì shàng mén bàifǎng wǒmen.
他明天会上门拜访我们。
He will visit us tomorrow.
Wǎnfàn hòu bié wàngle shàng mén.
晚饭后别忘了上门。
Don't forget to lock the door after dinner.
Diànpù yīn shēngyì bù hǎo bìxū shàngmén.
店铺因生意不好必须上门。
The shop has to close due to poor business.
Tā juédìng shàngmén zuò yīgè nǚxù.
他决定上门做一个女婿。
He decided to move in with his wife's family and become a son-in-law.