Q:

The different between MessageBoxService and Messenger in MVVM Winforms

Please give me the definition and the different between MessageBoxService and Messenger in MVVM Winforms and how to use it in project.

A:

The MessageBox service is designed to accomplish user-interaction: show some messages or take the confirmation.
Like any other service, in DevExpress MVVM Framework it introduced as a kind of IOC pattern that removes any references between a ViewModel and View layers. The main idea is to get an interface at the ViewModes side that does not honor any implementation details related on how which specific implementation is provided at the View side (it can be implemented as a standard or DevExpress Message Box or Flyout Dialog):
public void SayHello() {
    MessageBoxService.Show("Hello!");
}

I suggest you read more in the following help article: Services.
The Messenger is a mechanism of ViewModels communication that allows ViewModels to notify each other and share some data:
I suggest you read more in the following help article: Layers Communication. Messenger.

