Cylinder with switchable system and shock absorber having the same

A cylinder adapted for a shock absorber comprising:

• a cylinder body having an inner surface that defines a disposing space;
• a piston movably disposed in said disposing space, and dividing said disposing space into a liquid space that is adapted for a damping liquid to flow therein, and an air space that is adapted for a gas to be filled in;
• a cover mounted to said cylinder body such that said air space of said cylinder body is enclosed;
• and
• an electronic control device disposed in said air space of said cylinder body, dividing said air space into a first chamber space and a second chamber space, and having
• a chamber communicating opening through which said first chamber space and said second chamber space fluidly communicate with each other,
• an electromagnetic unit that generates a magnetic field when energised, and
• a rod unit that includes a blocking member and that is controllable by said electromagnetic unit to convert between a blocking state, in which said blocking member blocks said chamber communicating opening to prevent fluid communication between said first chamber space and said second chamber space, and an unblocking state, in which said blocking member unblocks said chamber communicating opening to permit fluid communication between said first chamber space and said second chamber space.