MVC and MVVM Patterns in Software Design

Model-View-Controller (MVC) Pattern

• MVC is a software design pattern used to implement user interfaces, data, and controlling logic.
• It emphasizes a separation between the software's business logic and display, providing a better division of labor and improved maintenance.
• MVC provides a clear separation of business logic, UI logic, and input logic.
• It offers full control over HTML and URLs, making it easy to design web application architecture.
• MVC supports Test Driven Development (TDD).

Components of MVC

• Model: Manages data and business logic. Defines what data the app should contain. Notifies the view and sometimes the controller if the state of the data changes.
• View: Handles layout and display. Defines how the app's data should be displayed. Created by the data collected by the model component, but not directly taken from the model.
• Controller: Contains logic that updates the model and/or view in response to input from the users of the app.

Advantages of MVC

• Easy to maintain and extend codes
• Supports TDD
• Components can be developed simultaneously
• Reduces complexity by dividing an application into three units
• Works well for Web apps supported by large teams of web designers and developers
• SEO friendly

Disadvantages of MVC

• Difficult to read, change, test, and reuse
• Not suitable for building small applications
• Inefficient data access in view
• Framework navigation can be complex
• Increased complexity and inefficiency of data access

Model-View-ViewModel (MVVM) Pattern

• MVVM is a software design pattern that separates program logic and user interface controls.
• It is structured to separate program logic and user interface controls.

Components of MVVM

• Model: Represents the app's domain model, including data model, business, and validation logic. Communicates with the ViewModel.
• View: Collects visible elements, receives user input, and does not interact with the Model directly.
• ViewModel: Located between the View and Model layers, contains logic for interacting with the View, and binds the UI elements in View to the controls in ViewModel.

Advantages of MVVM

• Easier to develop, test, and maintain
• Separation of View from logic allows different teams to work on different components simultaneously
• Easier to test, as ViewModel and Model are independent from the View
• Code is simpler and cleaner, making it easier to understand and implement new features

Disadvantages of MVVM

• Complexity, especially when creating simple user interfaces
• Difficult to debug due to declarative data binding
• Can be overkill for simple projects

MVC Pattern

• A software design pattern used to implement user interfaces, data, and controlling logic.
• Emphasizes a separation between the software's business logic and display.
• Provides a clear separation of business logic, UI logic, and input logic.
• Offers full control over HTML and URLs, making it easy to design web application architecture.
• Features: powerful URL-mapping component, supports Test Driven Development (TDD).

The Three Parts of MVC

• Model: Manages data and business logic. Notifies the view and sometimes the controller if its state changes.
• View: Handles layout and display. Defines how the app's data should be displayed.
• Controller: Routes commands to the model and view parts.

MVVM Pattern

• A software design pattern that separates program logic and user interface controls.
• Also known as model-view-binder, created by Microsoft architects Ken Cooper and John Gossman.
• Used in Windows Presentation Foundation (WPF) and Silverlight.

The Separate Code Layers of MVVM

• Model: Represents the app's domain model, including data model, business, and validation logic. Communicates with the ViewModel.
• View: The collection of visible elements, receives user input. Includes user interfaces (UI), animations, and text.
• ViewModel: Located between the View and Model layers, houses controls for interacting with View, and binds UI elements to controls.

MVVM vs. MVC

• Mediator: In MVC, the mediator is the Controller, while in MVVM, it's the ViewModel.
• Logic: In MVC, the View contains logic, whereas in MVVM, the logic resides in the ViewModel.
• Reference: In MVC, the View doesn't have a reference to the Controller, but in MVVM, the View has a reference to the ViewModel.

Advantages of MVVM

• Easier to develop: Separation of View and logic allows for simultaneous work on different components.
• Easier to test: ViewModel and Model are independent of the View, making it easier to write tests.
• Easier to maintain: Separation of components makes the code simpler and cleaner.

Disadvantages of MVVM

• Complexity: MVVM can be overkill for simple user interfaces, and designing the ViewModel can be difficult.
• Debugging: Declarative data binding can make debugging harder than traditional, imperative code.