A bracket device ,comprising: a bracket comprising a longitudinal wall and at least one mounting member mounted adjacent to the longitudinal wall ; a fastening member longitudinally displaceable with respect to the bracket , and the fastening member comprising a side wall and a fastening portion bent with respect to the side wall ; and a resilient member for providing a resilient force to the bracket and the fastening member ; wherein the bracket is arranged with a first engaging feature , and the fastening member is arranged with a second engaging feature ; wherein when the fastening member displaces with respect to the bracket from an unlocking position (P1) to a locking position (P2), the fastening portion is close to the at least one mounting member , and the first engaging feature is engaged with the second engaging feature , such that the fastening member is kept at the locking position (P2) with respect to the bracket , and the resilient member maintains the resilient force; wherein the resilient force is for recovering the fastening member to the unlocking position (PI); wherein the bracket device further comprises an engaging member , the engaging member comprises a connecting portion and a resilient arm , the connecting portion is connected to the longitudinal wall of the bracket , the resilient arm is extended from the connecting portion , and the resilient arm has the first engaging feature for being engaged with the second engaging feature of the side wall of the fastening member when the fastening member is at the locking position (P2); characterized in that an elongated hole is formed on the side wall of the fastening member , the bracket device further comprises an operating member , the operating member has a fixing portion and an operating portion , the fixing portion is connected to the longitudinal wall of the bracket via a fixing member passing through the elongated hole , the operating portion is flexibly connected to the fixing portion , the operating portion has a contacting feature passing through the elongated hole , and the contacting feature is corresponding to the resilient arm of the engaging member . a bracket comprising a longitudinal wall and at least one mounting member mounted adjacent to the longitudinal wall ; a fastening member longitudinally displaceable with respect to the bracket , and the fastening member comprising a side wall and a fastening portion bent with respect to the side wall ; and a resilient member for providing a resilient force to the bracket and the fastening member ; wherein the bracket is arranged with a first engaging feature , and the fastening member is arranged with a second engaging feature ; wherein when the fastening member displaces with respect to the bracket from an unlocking position (P1) to a locking position (P2), the fastening portion is close to the at least one mounting member , and the first engaging feature is engaged with the second engaging feature , such that the fastening member is kept at the locking position (P2) with respect to the bracket , and the resilient member maintains the resilient force; wherein the resilient force is for recovering the fastening member to the unlocking position (PI); wherein the bracket device further comprises an engaging member , the engaging member comprises a connecting portion and a resilient arm , the connecting portion is connected to the longitudinal wall of the bracket , the resilient arm is extended from the connecting portion , and the resilient arm has the first engaging feature for being engaged with the second engaging feature of the side wall of the fastening member when the fastening member is at the locking position (P2); <EOS>