Binding to commands in WinForms

Question

How can a button be bound to a command in a view model like in WPF with MVVM?

Answer 1

I was wondering if the same thing could be done and ended writing a simple CommandManager that queries the registered commands (on the Application.Idle event) and uses databinding to change the Enabled state of the control

This is the code I'm using right now:

public class CommandManager: Component {     private IList<ICommand> Commands { get; set; }     private IList<ICommandBinder> Binders { get; set; }      public CommandManager()     {         Commands = new List<ICommand>();          Binders = new List<ICommandBinder>                       {                           new ControlBinder(),                           new MenuItemCommandBinder()                       };          Application.Idle += UpdateCommandState;     }      private void UpdateCommandState(object sender, EventArgs e)     {         Commands.Do(c => c.Enabled);     }      public CommandManager Bind(ICommand command, IComponent component)     {         if (!Commands.Contains(command))             Commands.Add(command);          FindBinder(component).Bind(command, component);         return this;     }      protected ICommandBinder FindBinder(IComponent component)     {         var binder = GetBinderFor(component);          if (binder == null)             throw new Exception(string.Format("No binding found for component of type {0}", component.GetType().Name));          return binder;     }      private ICommandBinder GetBinderFor(IComponent component)     {         var type = component.GetType();         while (type != null)         {             var binder = Binders.FirstOrDefault(x => x.SourceType == type);             if (binder != null)                 return binder;              type = type.BaseType;         }          return null;     }      protected override void Dispose(bool disposing)     {         if (disposing)             Application.Idle -= UpdateCommandState;          base.Dispose(disposing);     } }  public static class Extensions {     public static void Do<T>(this IEnumerable<T> @this, Func<T, object> lambda)     {         foreach (var item in @this)             lambda(item);     } } public abstract class CommandBinder<T> : ICommandBinder where T: IComponent {     public Type SourceType     {         get { return typeof (T); }     }      public void Bind(ICommand command, object source)     {         Bind(command, (T) source);      }      protected abstract void Bind(ICommand command, T source); }  public class ControlBinder: CommandBinder<Control> {     protected override void Bind(ICommand command, Control source)     {         source.DataBindings.Add("Enabled", command, "Enabled");         source.DataBindings.Add("Text", command, "Name");         source.Click += (o, e) => command.Execute();     } }  public class MenuItemCommandBinder : CommandBinder<ToolStripItem> {     protected override void Bind(ICommand command, ToolStripItem source)     {         source.Text = command.Name;         source.Enabled = command.Enabled;         source.Click += (o, e) => command.Execute();          command.PropertyChanged += (o, e) => source.Enabled = command.Enabled;     } } 

and this is an exmaple of how to use it:

public partial class Form1 : Form {     private CommandManager commandManager;      public ICommand CommandA { get; set; }     public ICommand CommandB { get; set; }      public bool condition;      public Form1()     {         InitializeComponent();          commandManager = new CommandManager();          CommandA = new DelegateCommand("Command 1", OnTrue, OnExecute);         CommandB = new DelegateCommand("Command 2", OnFalse, OnExecute);          commandManager.Bind(CommandA, button1);         commandManager.Bind(CommandB, button2);          commandManager.Bind(CommandA, command1ToolStripMenuItem);         commandManager.Bind(CommandB, command2ToolStripMenuItem);     }      private bool OnFalse()     {         return !condition;     }      private bool OnTrue()     {         return condition;     }      private void OnExecute()     {         condition = !condition;     } } 

Also if you need the code, I blogged about it here