Inside a ZUL file using the MVVM @command annotation within a component event there is no way to include a preliminary prompt for the user to confirm the selected action.

For example, assume that a user has a button called 'delete' and clicking on this will delete an entry from a list. Using the syntax...

<button label="Delete" onClick="@command('delete')" />

... there isn't a way inside the ZUL to inject a preliminary prompt of the type "are you sure you want to delete?". The only way to achieve this is to use a Messagebox code inside the MVVM view class method. And that has to be bad as it injects GUI into what should be a non GUI method handler.

One way of providing a preliminary prompt for @command actions would be to introduce a new '@confirm' annotation. Something like...

<button label="Delete" onClick="@confirm(vm.confirmDelete,YES) @command('delete')" />

The @confirm annotation would take two parameters:

• a view model property of the type Messagebox
• a Messagebox button value that is the value that confirms whether the process is to proceed onto the @command step