A case includes a shell, a sliding member, and an operating member. The shell defines a through hole. The sliding member includes an abutting portion. The operating member is rotatably fixed to the shell and slidably connected to the sliding member. The operating member rotates in a first direction to drive the sliding member to slide in a second direction and the abutting portion abuts the stopping portion to be pushed out of the through hole. The operating member rotates in a direction opposite to the first direction to drive the sliding member to slide in a direction opposite to the second direction and the stopping portion moves into the through hole.