Smart WPF Login Overlay (Windows 8 Style)

//	--------------------------------------------------------------------
//		Member of the WPFSmartLibrary
//		For more information see : http://wpfsmartlibrary.codeplex.com/
//		(by DotNetMastermind)
//
//		filename		: ActionCommand.cs
//		namespace	: SoftArcs.WPFSmartLibrary.MVVMCommands
//		class(es)	: ActionCommand
//							
//	--------------------------------------------------------------------
using System;
using System.Windows.Input;

namespace SoftArcs.WPFSmartLibrary.MVVMCommands
{
	/// <summary>
	/// This class is similar to the "ActionCommand"-class from the 'Microsoft.Expression.Interactivity.Core'-namespace
	/// which is included in the 'Microsoft.Expression.Interactions.dll' from the Microsoft Blend 4 SDK
	/// (so you do not need to install the SDK to use this command)
	/// </summary>
	public class ActionCommand : ICommand
	{
		private readonly Action executeHandler;
		private readonly Action<object> executeHandlerWithParameter;
		private readonly Func<object, bool> canExecuteHandler;

		/// <summary>
		/// Parameterless version of the ActionCommand
		/// </summary>
		/// <param name="execute"></param>
		public ActionCommand(Action execute)
		{
			if (execute == null)
			{
				throw new ArgumentNullException( "Execute can't be null", new Exception() );
			}

			this.executeHandler = execute;
		}

		/// <summary>
		/// ActionCommand with an object-parameter
		/// </summary>
		/// <param name="execute"></param>
		public ActionCommand(Action<object> execute)
		{
			if (execute == null)
			{
				throw new ArgumentNullException( "Execute can't be null", new Exception() );
			}

			this.executeHandlerWithParameter = execute;
		}

		/// <summary>
		/// ActionCommand with an object-parameter and a CanExecute delegate
		/// </summary>
		/// <param name="execute"></param>
		/// <param name="canExecute"> </param>
		public ActionCommand(Action<object> execute, Func<object, bool> canExecute)
			: this( execute )
		{
			this.canExecuteHandler = canExecute;
		}

		#region Members of the 'ICommand' interface

		public void Execute(object args)
		{
			if (this.executeHandlerWithParameter != null)
			{
				this.executeHandlerWithParameter( args );
			}
			else
			{
				this.executeHandler();
			}
		}

		public bool CanExecute(object args)
		{
			if (this.canExecuteHandler == null)
			{
				return true;
			}

			return this.canExecuteHandler( args );
		}

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

		#endregion // Members of the 'ICommand' interface
	}
}