Clarify that ICommand.CanExecuteChanged must be raised manually in .NET MAUI

docs/fundamentals/data-binding/commanding.md

@@ -51,12 +51,15 @@ When the user presses the <xref:Microsoft.Maui.Controls.Button>, the <xref:Micro
 
 When the binding is first defined on the `Command` property of the <xref:Microsoft.Maui.Controls.Button>, and when the data binding changes in some way, the <xref:Microsoft.Maui.Controls.Button> calls the `CanExecute` method in the <xref:System.Windows.Input.ICommand> object. If `CanExecute` returns `false`, then the <xref:Microsoft.Maui.Controls.Button> disables itself. This indicates that the particular command is currently unavailable or invalid.
 
-The <xref:Microsoft.Maui.Controls.Button> also attaches a handler on the `CanExecuteChanged` event of <xref:System.Windows.Input.ICommand>. The event is raised from within the viewmodel. When that event is raised, the <xref:Microsoft.Maui.Controls.Button> calls `CanExecute` again. The <xref:Microsoft.Maui.Controls.Button> enables itself if `CanExecute` returns `true` and disables itself if `CanExecute` returns `false`.
+The <xref:Microsoft.Maui.Controls.Button> also attaches a handler on the `CanExecuteChanged` event of <xref:System.Windows.Input.ICommand>. The event must be raised manually from within the viewmodel whenever conditions change that affect the `CanExecute` result. When that event is raised, the <xref:Microsoft.Maui.Controls.Button> calls `CanExecute` again. The <xref:Microsoft.Maui.Controls.Button> enables itself if `CanExecute` returns `true` and disables itself if `CanExecute` returns `false`.
+
+> [!IMPORTANT]
+> Unlike some UI frameworks (such as WPF), .NET MAUI does not automatically detect when the return value of `CanExecute` might change. You must manually raise the `CanExecuteChanged` event (or call `ChangeCanExecute()` on the `Command` class) whenever any condition changes that would affect the `CanExecute` result. This is typically done when properties that `CanExecute` depends on are modified.
 
 > [!WARNING]
 > Do not use the `IsEnabled` property of <xref:Microsoft.Maui.Controls.Button> if you're using the command interface.  
 
-When your viewmodel defines a property of type <xref:System.Windows.Input.ICommand>, the viewmodel must also contain or reference a class that implements the <xref:System.Windows.Input.ICommand> interface. This class must contain or reference the `Execute` and `CanExecute` methods, and fire the `CanExecuteChanged` event whenever the `CanExecute` method might return a different value. You can use the `Command` or `Command<T>` class included in .NET MAUI to implement the <xref:System.Windows.Input.ICommand> interface. These classes allow you to specify the bodies of the `Execute` and `CanExecute` methods in class constructors.
+When your viewmodel defines a property of type <xref:System.Windows.Input.ICommand>, the viewmodel must also contain or reference a class that implements the <xref:System.Windows.Input.ICommand> interface. This class must contain or reference the `Execute` and `CanExecute` methods, and manually fire the `CanExecuteChanged` event whenever the `CanExecute` method might return a different value. You can use the `Command` or `Command<T>` class included in .NET MAUI to implement the <xref:System.Windows.Input.ICommand> interface. These classes allow you to specify the bodies of the `Execute` and `CanExecute` methods in class constructors.
 
 > [!TIP]
 > Use `Command<T>` when you use the `CommandParameter` property to distinguish between multiple views bound to the same <xref:System.Windows.Input.ICommand> property, and the `Command` class when that isn't a requirement.
@@ -296,7 +299,7 @@ public class PersonCollectionViewModel : INotifyPropertyChanged
 
 When the user clicks the **New** button, the `execute` function passed to the `Command` constructor is executed. This creates a new `PersonViewModel` object, sets a handler on that object's `PropertyChanged` event, sets `IsEditing` to `true`, and calls the `RefreshCanExecutes` method defined after the constructor.
 
-Besides implementing the <xref:System.Windows.Input.ICommand> interface, the `Command` class also defines a method named `ChangeCanExecute`. A viewmodel should call `ChangeCanExecute` for an <xref:System.Windows.Input.ICommand> property whenever anything happens that might change the return value of the `CanExecute` method. A call to `ChangeCanExecute` causes the `Command` class to fire the `CanExecuteChanged` method. The <xref:Microsoft.Maui.Controls.Button> has attached a handler for that event and responds by calling `CanExecute` again, and then enabling itself based on the return value of that method.
+Besides implementing the <xref:System.Windows.Input.ICommand> interface, the `Command` class also defines a method named `ChangeCanExecute`. Your viewmodel must call `ChangeCanExecute` for an <xref:System.Windows.Input.ICommand> property whenever anything happens that might change the return value of the `CanExecute` method. A call to `ChangeCanExecute` causes the `Command` class to fire the `CanExecuteChanged` event. The <xref:Microsoft.Maui.Controls.Button> has attached a handler for that event and responds by calling `CanExecute` again, and then enabling itself based on the return value of that method.
 
 When the `execute` method of `NewCommand` calls `RefreshCanExecutes`, the `NewCommand` property gets a call to `ChangeCanExecute`, and the <xref:Microsoft.Maui.Controls.Button> calls the `canExecute` method, which now returns `false` because the `IsEditing` property is now `true`.