A bracket device , comprising: a sidewall ; a base adjacent to the sidewall ; at least one mounting member connected to the base ; the bracket device further comprises an elastic member and a fastening member , wherein the fastening member is pivotally mounted on the sidewall , the fastening member includes an engaging structure and is configured to stay in a first state (P1) responsive to an elastic force provided by the elastic member ; and wherein the fastening member includes a lateral portion and at least one fastening portion which is bent with respect to the lateral portion , and wherein the engaging structure of the fastening member includes a space and at least one blocking wall adjacent to the space, and wherein the engaging structure is configured for engaging with a target member, and wherein the fastening member is switchable from the first state (P1) to a second state (P2) by operation, wherein the lateral portion includes the engaging structure , the fastening portion is adjacent to the at least one mounting member when the fastening member is in the first state (P1), and the fastening portion is away from the at least one mounting member when the fastening member is in the second state (P2), characterized in that the engaging structure is located at the fastening portion , the engaging structure includes an extension arm and a hook portion bent with respect to the extension arm , and the lateral portion, the fastening portion of the fastening member, the extension arm and the hook portion of the engaging structure are integrally formed, and wherein the fastening portion is adjacent to the at least one mounting member when the fastening member is in the first state (P1) and/or the extension arm of the engaging structure is substantially perpendicularly connected to the fastening portion . a sidewall ; a base adjacent to the sidewall ; at least one mounting member connected to the base ; the bracket device further comprises an elastic member and a fastening member , wherein the fastening member is pivotally mounted on the sidewall , the fastening member includes an engaging structure and is configured to stay in a first state (P1) responsive to an elastic force provided by the elastic member ; and wherein the fastening member includes a lateral portion and at least one fastening portion which is bent with respect to the lateral portion , and wherein the engaging structure of the fastening member includes a space and at least one blocking wall adjacent to the space, and wherein the engaging structure is configured for engaging with a target member, and wherein the fastening member is switchable from the first state (P1) to a second state (P2) by operation, wherein the lateral portion includes the engaging structure , the fastening portion is adjacent to the at least one mounting member when the fastening member is in the first state (P1), and the fastening portion is away from the at least one mounting member when the fastening member is in the second state (P2), characterized in that the engaging structure is located at the fastening portion , the engaging structure includes an extension arm and a hook portion bent with respect to the extension arm , and the lateral portion, the fastening portion of the fastening member, the extension arm and the hook portion of the engaging structure are integrally formed, and wherein the fastening portion is adjacent to the at least one mounting member when the fastening member is in the first state (P1) and/or the extension arm of the engaging structure is substantially perpendicularly connected to the fastening portion . <EOS>