//******************************************************************************************************//  RelayCommand.cs - Gbtc////  Copyright © 2012, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may//  not use this file except in compliance with the License. You may obtain a copy of the License at:////      http://www.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  03/28/2011 - Mehulbhai P Thakkar//       Generated original version of source code.//       This code is based on MVVM Design Pattern article by Josh Smith - MSDN magazine, Feb 2009.//  04/11/2011 - J. Ritchie Carroll//       Created delegate wrapper contructor for common case when methods use no parameters.//       Added code comments.//  12/20/2012 - Starlynn Danyelle Gilliam//       Modified Header.////****************************************************************************************************** using System;using System.Windows.Input; namespace GSF.TimeSeries.UI.Commands{    /// <summary>    /// Defines a relay <see cref="ICommand"/>.    /// </summary>    public class RelayCommand : ICommand    {        #region [ Members ]         // Events         /// <summary>        /// Occurs when changes occur that affect whether or not the command should execute.        /// </summary>        public event EventHandler CanExecuteChanged        {            add            {                CommandManager.RequerySuggested += value;            }            remove            {                CommandManager.RequerySuggested -= value;            }        }         // Fields        private readonly Action<object> m_execute;        private readonly Predicate<object> m_canExecute;         #endregion         #region [ Constructors ]         /// <summary>        /// Creates a new <see cref="RelayCommand"/> for the common case delegates.        /// </summary>        /// <param name="execute">Execute method pointer.</param>        /// <param name="canExecute">Can execute method pointer.</param>        public RelayCommand(Action execute, Func<bool> canExecute = null)        {            if (execute == null)                throw new ArgumentNullException(nameof(execute));             // Create lambda proxies for delegates that use no parameters            m_execute = param => execute();             if (canExecute == null)                m_canExecute = null;            else                m_canExecute = param => canExecute();        }         /// <summary>        /// Creates a new <see cref="RelayCommand"/>.        /// </summary>        /// <param name="execute">Execute method pointer.</param>        /// <param name="canExecute">Can execute method pointer.</param>        public RelayCommand(Action<object> execute, Predicate<object> canExecute = null)        {            if (execute == null)                throw new ArgumentNullException(nameof(execute));             m_execute = execute;            m_canExecute = canExecute;        }         #endregion         #region [ Methods ]         /// <summary>        /// Defines the method that determines whether the command can execute in its current state.        /// </summary>        /// <param name="parameter">        /// Data used by the <see cref="RelayCommand"/>. If the <see cref="RelayCommand"/> does not require        /// data to be passed, this object can be set to <c>null</c>.        /// </param>        /// <returns><c>true</c> if this <see cref="RelayCommand"/> can be executed; otherwise, <c>false</c>.</returns>        public bool CanExecute(object parameter)        {            return m_canExecute == null ? true : m_canExecute(parameter);        }         /// <summary>        /// Defines the method to be called when the command is invoked.        /// </summary>        /// <param name="parameter">        /// Data used by the <see cref="RelayCommand"/>. If the <see cref="RelayCommand"/> does not require        /// data to be passed, this object can be set to <c>null</c>.        /// </param>        public void Execute(object parameter)        {            m_execute(parameter);        }         #endregion    }}