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using System;
using System.Windows.Input;
namespace Xamarin.Forms
{
public class MenuItem : BaseMenuItem
{
public static readonly BindableProperty TextProperty = BindableProperty.Create("Text", typeof(string), typeof(MenuItem), null);
public static readonly BindableProperty CommandProperty = BindableProperty.Create("Command", typeof(ICommand), typeof(MenuItem), null,
propertyChanging: (bo, o, n) => ((MenuItem)bo).OnCommandChanging(), propertyChanged: (bo, o, n) => ((MenuItem)bo).OnCommandChanged());
public static readonly BindableProperty CommandParameterProperty = BindableProperty.Create("CommandParameter", typeof(object), typeof(MenuItem), null,
propertyChanged: (bo, o, n) => ((MenuItem)bo).OnCommandParameterChanged());
public static readonly BindableProperty IsDestructiveProperty = BindableProperty.Create("IsDestructive", typeof(bool), typeof(MenuItem), false);
public static readonly BindableProperty IconProperty = BindableProperty.Create("Icon", typeof(FileImageSource), typeof(MenuItem), default(FileImageSource));
internal static readonly BindableProperty IsEnabledProperty = BindableProperty.Create("IsEnabled", typeof(bool), typeof(ToolbarItem), true);
public ICommand Command
{
get { return (ICommand)GetValue(CommandProperty); }
set { SetValue(CommandProperty, value); }
}
public object CommandParameter
{
get { return GetValue(CommandParameterProperty); }
set { SetValue(CommandParameterProperty, value); }
}
public FileImageSource Icon
{
get { return (FileImageSource)GetValue(IconProperty); }
set { SetValue(IconProperty, value); }
}
public bool IsDestructive
{
get { return (bool)GetValue(IsDestructiveProperty); }
set { SetValue(IsDestructiveProperty, value); }
}
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
internal bool IsEnabled
{
get { return (bool)GetValue(IsEnabledProperty); }
set { SetValue(IsEnabledProperty, value); }
}
bool IsEnabledCore
{
set { SetValueCore(IsEnabledProperty, value); }
}
public event EventHandler Clicked;
protected virtual void OnClicked()
{
EventHandler handler = Clicked;
if (handler != null)
handler(this, EventArgs.Empty);
}
internal void Activate()
{
if (Command != null)
{
if (IsEnabled)
Command.Execute(CommandParameter);
}
OnClicked();
}
void OnCommandCanExecuteChanged(object sender, EventArgs eventArgs)
{
IsEnabledCore = Command.CanExecute(CommandParameter);
}
void OnCommandChanged()
{
if (Command == null)
{
IsEnabledCore = true;
return;
}
IsEnabledCore = Command.CanExecute(CommandParameter);
Command.CanExecuteChanged += OnCommandCanExecuteChanged;
}
void OnCommandChanging()
{
if (Command == null)
return;
Command.CanExecuteChanged -= OnCommandCanExecuteChanged;
}
void OnCommandParameterChanged()
{
if (Command == null)
return;
IsEnabledCore = Command.CanExecute(CommandParameter);
}
}
}
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