Who knows the origin of "Dong Chuang son-in-law"?

Dong Chuang's son-in-law-Wang Xizhi. At the age of 20, A Qiu Chi Jian sent someone to Wang Dao's house to choose a son-in-law. At that time, people paid attention to family status, and the door was right. The single nobles of the Wang family heard that someone from the Qiu family was coming to propose marriage, and they all dressed up in disguise, hoping to be selected. Only Wang Xizhi, as if he didn't hear anything, lay on the bamboo couch in the east and didn't care. When people came back, they reported what they had seen to Captain Xi. When Qiu learned that the quiet man on the east couch was Wang Xizhi, he could not help clapping his hands and praising him: "This is the son-in-law I want." So,; Chi Jian married his daughter Xi Jun to Wang Xizhi; This story is the famous "son-in-law".