Windows Forms

Windows Forms

Trigger On

• working on Windows Forms UI, event-driven workflows, or classic LOB applications
• migrating WinForms from .NET Framework to modern .NET
• cleaning up oversized form code or designer coupling
• implementing data binding, validation, or control customization

Workflow

1. Respect designer boundaries — never edit .Designer.cs directly; changes are lost on regeneration.
2. Separate business logic from forms — use MVP (Model-View-Presenter) pattern. Forms orchestrate UI; presenters contain logic; services handle data access.

   // View interface — forms implement this
   public interface ICustomerView
   {
       string CustomerName { get; set; }
       event EventHandler SaveRequested;
       void ShowError(string message);
   }
   
   // Presenter — testable without UI
   public class CustomerPresenter
   {
       private readonly ICustomerView _view;
       private readonly ICustomerService _service;
       public CustomerPresenter(ICustomerView view, ICustomerService service)
       {
           _view = view;
           _service = service;
           _view.SaveRequested += async (s, e) =>
           {
               try { await _service.SaveAsync(_view.CustomerName); }
               catch (Exception ex) { _view.ShowError(ex.Message); }
           };
       }
   }
   

3. Use DI from Program.cs (.NET 6+):