Grass trimmer, operating method thereof and control method thereof

A grass trimmer, comprising:

• a trimming head;
• a driving device for driving the trimming head to rotate so as to cut vegetation;
• and
• an operating device configured for a user to operate to control the grass trimmer;
• wherein the trimming head comprises a spool and a line holding member, the spool is used to wind a cutting line, and the line holding member includes a line holding structure allowing the cutting line to pass through or bypass,
• wherein the driving device comprises a motor, the grass trimmer has a cutting mode for cutting vegetation and an auto-winding mode for winding the cutting line onto the spool, in the auto-winding mode, the motor drives at least one of the spool and the line holding member to make the spool and the line holding member rotate relatively to wind the cutting line on the spool, and
• the operating device comprises a first operating element for activating the cutting mode and a second operating element for activating the auto-winding mode.