在焦点丢失之前更新视图模型或在维护Tab键顺序时如何限制命令

In WPF, when designing forms, it is common to disable form elements (such as buttons/commands or entire areas) in response to the state of the View Model. This is easily done by having the CanExecute check the various properties on the View Model.In WPF, when designing forms, it is common to d