// <copyright file="RelayCommand.cs" company="GalaSoft Laurent Bugnion">
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// Copyright © GalaSoft Laurent Bugnion 2009-2013
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// </copyright>
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// ****************************************************************************
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// <author>Laurent Bugnion</author>
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// <email>laurent@galasoft.ch</email>
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// <date>22.4.2009</date>
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// <project>BioNano.Common.Framework.Mvvm</project>
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// <web>http://www.galasoft.ch</web>
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// <license>
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// See license.txt in this project or http://www.galasoft.ch/license_MIT.txt
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// </license>
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// <LastBaseLevel>BL0011</LastBaseLevel>
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// ****************************************************************************
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// <credits>This class was developed by Josh Smith (http://joshsmithonwpf.wordpress.com) and
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// slightly modified with his permission.</credits>
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// ****************************************************************************
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using System;
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using System.Diagnostics.CodeAnalysis;
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using System.Windows.Input;
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////using GalaSoft.Utilities.Attributes;
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namespace Bro.Common.ImageCanvas
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{
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/// <summary>
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/// A command whose sole purpose is to relay its functionality to other
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/// objects by invoking delegates. The default return value for the CanExecute
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/// method is 'true'. This class does not allow you to accept command parameters in the
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/// Execute and CanExecute callback methods.
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/// </summary>
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////[ClassInfo(typeof(RelayCommand),
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//// Description = "A command whose sole purpose is to relay its functionality to other objects by invoking delegates.",
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//// UrlContacts = "http://www.galasoft.ch/contact_en.html",
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//// Email = "laurent@galasoft.ch")]
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internal class RelayCommand : ICommand
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{
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private readonly Action _execute;
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private readonly Func<bool> _canExecute;
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/// <summary>
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/// Initializes a new instance of the RelayCommand class that
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/// can always execute.
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/// </summary>
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/// <param name="execute">The execution logic.</param>
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/// <exception cref="ArgumentNullException">If the execute argument is null.</exception>
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public RelayCommand(Action execute)
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: this(execute, null)
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{
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}
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/// <summary>
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/// Initializes a new instance of the RelayCommand class.
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/// </summary>
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/// <param name="execute">The execution logic.</param>
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/// <param name="canExecute">The execution status logic.</param>
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/// <exception cref="ArgumentNullException">If the execute argument is null.</exception>
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public RelayCommand(Action execute, Func<bool> canExecute)
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{
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if (execute == null)
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{
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throw new ArgumentNullException(nameof(execute));
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}
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_execute = execute;
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if (canExecute != null)
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{
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_canExecute = canExecute;
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}
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}
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#if SILVERLIGHT
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/// <summary>
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/// Occurs when changes occur that affect whether the command should execute.
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/// </summary>
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public event EventHandler CanExecuteChanged;
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#else
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#if NETFX_CORE
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/// <summary>
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/// Occurs when changes occur that affect whether the command should execute.
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/// </summary>
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public event EventHandler CanExecuteChanged;
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#else
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#if XAMARIN
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/// <summary>
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/// Occurs when changes occur that affect whether the command should execute.
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/// </summary>
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public event EventHandler CanExecuteChanged;
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#else
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/// <summary>
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/// Occurs when changes occur that affect whether the command should execute.
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/// </summary>
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public event EventHandler CanExecuteChanged
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{
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add
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{
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if (_canExecute != null)
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CommandManager.RequerySuggested += value;
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}
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remove
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{
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if (_canExecute != null)
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CommandManager.RequerySuggested -= value;
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}
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}
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#endif
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#endif
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#endif
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/// <summary>
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/// Raises the <see cref="CanExecuteChanged" /> event.
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/// </summary>
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[SuppressMessage(
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"Microsoft.Performance",
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"CA1822:MarkMembersAsStatic",
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Justification = "The this keyword is used in the Silverlight version")]
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[SuppressMessage(
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"Microsoft.Design",
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"CA1030:UseEventsWhereAppropriate",
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Justification = "This cannot be an event")]
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public void RaiseCanExecuteChanged()
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{
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#if SILVERLIGHT
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var handler = CanExecuteChanged;
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if (handler != null)
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{
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handler(this, EventArgs.Empty);
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}
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#else
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#if NETFX_CORE
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var handler = CanExecuteChanged;
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if (handler != null)
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{
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handler(this, EventArgs.Empty);
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}
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#else
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#if XAMARIN
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var handler = CanExecuteChanged;
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if (handler != null)
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{
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handler(this, EventArgs.Empty);
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}
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#else
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CommandManager.InvalidateRequerySuggested();
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#endif
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#endif
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#endif
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}
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/// <summary>
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/// Defines the method that determines whether the command can execute in its current state.
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/// </summary>
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/// <param name="parameter">This parameter will always be ignored.</param>
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/// <returns>true if this command can be executed; otherwise, false.</returns>
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public bool CanExecute(object parameter)
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{
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return _canExecute == null || _canExecute();
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}
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/// <summary>
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/// Defines the method to be called when the command is invoked.
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/// </summary>
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/// <param name="parameter">This parameter will always be ignored.</param>
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public virtual void Execute(object parameter)
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{
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if (CanExecute(parameter))
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_execute?.Invoke();
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}
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}
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}
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