Create EventToCommand.Picker.SelectedIndexChanged.cs

NuGet/RapidXaml.MAUI/EventToCommand/EventToCommand.Picker.SelectedIndexChanged.cs

@@ -0,0 +1,67 @@
+using System.Windows.Input;
+
+namespace RapidXaml;
+
+public partial class EventToCommand : BindableObject
+{
+	public static ICommand GetSelectedIndexChanged(BindableObject obj)
+		=> (ICommand)obj.GetValue(SelectedIndexChangedProperty);
+
+	public static void SetSelectedIndexChanged(BindableObject obj, ICommand value)
+		=> obj.SetValue(SelectedIndexChangedProperty, value);
+
+	public static readonly BindableProperty SelectedIndexChangedProperty =
+		BindableProperty.CreateAttached("SelectedIndexChanged", typeof(ICommand), typeof(EventToCommand), defaultValue: null, propertyChanged: OnSelectedIndexChangedChanged);
+
+	private static void OnSelectedIndexChangedChanged(BindableObject bindable, object oldValue, object newValue)
+	{
+		if (bindable is Picker pckr)
+		{
+			if (oldValue is ICommand oldCmd)
+			{
+				for (int i = pckr.Behaviors.Count; i >= 0; i--)
+				{
+					if (pckr.Behaviors[i] is EventToCommandSelectedIndexChangedBehavior oldBehavior && oldBehavior.CommandToInvoke == oldCmd)
+					{
+						pckr.Behaviors.Remove(oldBehavior);
+						break;
+					}
+				}
+			}
+
+			if (newValue is ICommand newCmd)
+			{
+				pckr.Behaviors.Add(new EventToCommandSelectedIndexChangedBehavior { CommandToInvoke = newCmd });
+			}
+		}
+	}
+
+	internal partial class EventToCommandSelectedIndexChangedBehavior : Behavior<Picker>
+	{
+		// TODO: Does this need to be passed the index?
+		public ICommand? CommandToInvoke { get; set; }
+
+		protected override void OnAttachedTo(Picker pckr)
+		{
+			pckr.SelectedIndexChanged += OnPickerSelectedIndexChanged;
+			base.OnAttachedTo(pckr);
+		}
+
+		protected override void OnDetachingFrom(Picker pckr)
+		{
+			pckr.SelectedIndexChanged -= OnPickerSelectedIndexChanged;
+			base.OnDetachingFrom(pckr);
+		}
+
+		private void OnPickerSelectedIndexChanged(object? sender, EventArgs e)
+		{
+			if (this.CommandToInvoke != null)
+			{
+				if (this.CommandToInvoke.CanExecute(null))
+				{
+					this.CommandToInvoke.Execute(null);
+				}
+			}
+		}
+	}
+}