RelayCommand.cs

// Copyright (c) 2015 WildCardJoker
// Licensed under the MIT License: http://opensource.org/licenses/MIT
// Created: 2015-07-14
// Last Modified: 2015-07-25-8:28 PM

#region Using Directives

using System;
using System.Diagnostics;
using System.Windows.Input;

#endregion

namespace ContactViewModel
{
    /// <summary>
    ///     A command whose sole purpose is to relay its functionality to other
    ///     objects by invoking delegates. The default return value for the
    ///     CanExecute method is 'true'.
    /// </summary>
    public class RelayCommand : ICommand
    {
        #region Fields

        private readonly Predicate<object> _canExecute;
        private readonly Action<object> _execute;

        #endregion

        #region Constructors

        /// <summary>
        ///     Creates a new command.
        /// </summary>
        /// <param name="execute">The execution logic.</param>
        /// <param name="canExecute">The execution status logic.</param>
        public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)
        {
            if (execute == null)
            {
                throw new ArgumentNullException(nameof(execute));
            }

            _execute = execute;
            _canExecute = canExecute;
        }

        #endregion

        #region ICommand Members

        [DebuggerStepThrough]
        public bool CanExecute(object parameters)
        {
            return _canExecute == null || _canExecute(parameters);
        }

        public event EventHandler CanExecuteChanged
        {
            add { CommandManager.RequerySuggested += value; }
            remove { CommandManager.RequerySuggested -= value; }
        }

        public void Execute(object parameters)
        {
            _execute(parameters);
        }

        #endregion
    }
}