react withRouter 離開頁面觸發

componentDidMount(){
    this.props.router.setRouteLeaveHook(this.props.route, () => {
        //if (this.state.unsaved)
        return 'You have unsaved information, are you sure you want to leave this page?'
         //獲取通過connect包裹的對象
         this.refs[''].wrappedInstance.getFieldsValue()
    })
}