A first electronic device includes an electromagnetic component embedded in its connecting port and controlled to be activated during data transmission between the first electronic device and a second electronic device to which the first electronic device is connecting, or during memory accessing of the first electronic device. As the electromagnetic component is activated, an attraction force exists between the two connecting ports of the first and the second electronic devices such that a user of the first electronic device will feel a resistance when he/she tries to disconnect the first electronic device from the second electronic device.