DR controller pattern is a common design pattern in software programming, which is used to separate data from presentation layer. DR stands for data and presentation layer. This pattern is realized by introducing data into the controller object, and then the controller object processes the data and updates the presentation layer.

In DR controller mode, there are several common variants:

1. Model-View-Controller (MVC) mode: MVC mode is a classic variant of DR controller mode. It divides the application into three parts: model, view and controller. The model is responsible for processing data logic, the view is responsible for displaying user interface, and the controller coordinates the interaction between the model and the view.

2. Model-View-Presenter (MVP) mode: MVP mode is an improvement of MVC mode, which decouples the dependence between view and model and introduces a closer relationship: two-way communication between view and presenter. The view is responsible for displaying the interface and forwarding the user operation to the presentation layer, which processes the user operation and updates the view.

3. Model-View-View Model (MVVM) mode: MVVM mode is a mode based on data binding. In MVVM mode, the view automatically reflects the changes of the model through data binding. The model represents the data and business logic of the application, the view is responsible for displaying the interface, and ViewModel, as the middle layer, is responsible for converting the data of the model into a form that can be used by the view.

These are common variants of DR controller mode, and each variant has its specific purpose and applicable scenarios. By using these patterns, the maintainability, flexibility and reusability of the code can be realized.