To successfully convert a Windows Forms application to a Web application without needing to decouple the ViewModel or extract an API, we combine the LiveView and Streaming Rendering patterns.
LiveView Pattern: Enables real-time, interactive UIs by maintaining a persistent connection between client and server. The server handles rendering and logic, sending updates as the application's state changes, allowing dynamic content updates without full page reloads or extensive client-side JavaScript implementations.
Streaming Rendering: UI content is sent from the server to the client in small chunks as it’s generated, allowing users to view and interact with parts of the page immediately. This approach enables dynamic updates to specific portions of the page in response to user commands and asynchronously to internal parallel processes or external events.
By applying such patterns, we switch the Application architecture from this:
To this:
Our modernization process replaces the Windows Forms native OS rendering system with an HTML server-side renderer. The modernized architecture includes the following components:
Client Proxy: Relays raw HTML events to the server and updates the DOM based on the visual deltas sent by the server.
Full-Duplex Connection: Asynchronously streams commands and visual updates in near real-time.
Original Application Logic: HTML events are mapped to Windows Forms events and programmatically triggered in the original application logic. This initiates one or more business logic processes that modify the application state.
HTML Renderer: Directly bound to the application state, it reacts to its changes by generating new HTML code and computing the difference from the current visual state. Only this difference is sent back to the client.
