closing ngDialog in controller

i have two function , one for opening dialog and one for posting data to server and then close the dialog , the problem is i cant close dialog , here us the code

 vm.openCreateDialog = function () {

                 var Dialog = ngDialog.open({
                    template: 'user/create',
                    className: 'ngdialog-theme-default'
                })
            }
vm.createUser = function () {
           DataService.createUser(vm.user).then(function (response) {
                $log.log('promise returned successfully')
                Dialog.close();

            }).catch(function (e) {
                $log.log('catch registration error')

            });
}

ngDialog.open() return an object with id , the id is id of dialog box , I use it to close the dialog box , here is working code if anybody came to it

 vm.openCreateDialog = function () {

                 vm.Dialog = ngDialog.open({
                    template: 'user/create',
                    className: 'ngdialog-theme-default',

                 })
                 vm.dialogId = vm.Dialog.id;
            }

and from another function I just used the id to close dialog

  ngDialog.close(vm.dialogId)