Executing Command Logic in a View Model

using System;
using System.Reflection;
using System.Windows.Input;

namespace RoutedCommandBindingSample.Commands
{
    /// <summary>
    ///     The base class for <see cref="CommandBinding"/> types that invoke command logic in
    ///     locations other than the code behind file.
    /// </summary>
    public abstract class RoutedCommandBinding : CommandBinding
    {
        static RoutedCommandBinding()
        {
            RoutedCommandMonitor.Init();
        }
        
        /// <summary>
        ///     Indicates whether or not the methods associated with this
        ///     <see cref="RoutedCommandBinding"/> will be executed when the Handled property
        ///     of the <see cref="RoutedEventArgs"/> is set to true during the bubbling or
        ///     tunneling of the command's <see cref="RoutedEvent"/>.
        /// </summary>
        public bool ViewHandledEvents { get; set; }

        /// <summary>
        ///     Initializes a new instance of the <see cref="RoutedCommandBinding"/> class.
        /// </summary>
        public RoutedCommandBinding() { }

        /// <summary>
        ///     Initializes a new instance of the <see cref="RoutedCommandBinding"/> class by
        ///     using the specified <see cref="ICommand"/>.
        /// </summary>
        public RoutedCommandBinding(ICommand command)
            : base(command)
        { }

        /// <summary>
        ///     The method that is called when the PreviewCanExecute <see cref="RoutedEvent"/> for
        ///     the <see cref="ICommand"/> associated with this <see cref="RoutedCommandBinding"/>
        ///     should be handled. Inheriting types must provide an implementation for this method.
        /// </summary>
        /// <param name="sender">The command target on which the command is executing.</param>
        /// <param name="e">The event data.</param>
        protected internal abstract void OnPreviewCanExecute(object sender, CanExecuteRoutedEventArgs e);

        /// <summary>
        ///     The method that is called when the CanExecute <see cref="RoutedEvent"/> for the
        ///     <see cref="ICommand"/> associated with this <see cref="RoutedCommandBinding"/>
        ///     should be handled. Inheriting types must provide an implementation for this method.
        /// </summary>
        /// <param name="sender">The command target on which the command is executing.</param>
        /// <param name="e">The event data.</param>
        protected internal abstract void OnCanExecute(object sender, CanExecuteRoutedEventArgs e);

        /// <summary>
        ///     The method that is called when the PreviewExecuted <see cref="RoutedEvent"/> for
        ///     the <see cref="ICommand"/> associated with this <see cref="RoutedCommandBinding"/>
        ///     should be handled. Inheriting types must provide an implementation for this method.
        /// </summary>
        /// <param name="sender">The command target on which the command is executing.</param>
        /// <param name="e">The event data.</param>
        protected internal abstract void OnPreviewExecuted(object sender, ExecutedRoutedEventArgs e);
        
        /// <summary>
        ///     The method that is called when the Executed <see cref="RoutedEvent"/> for the
        ///     <see cref="ICommand"/> associated with this <see cref="RoutedCommandBinding"/>
        ///     should be handled. Inheriting types must provide an implementation for this method.
        /// </summary>
        /// <param name="sender">The command target on which the command is executing.</param>
        /// <param name="e">The event data.</param>
        protected internal abstract void OnExecuted(object sender, ExecutedRoutedEventArgs e);
    }
}