Raise context menu command's CanExcute while open the context menu

问题

Can Execute of a ICommand while a Context menu open

With the continuation of the above query, Still its not able to achieve.

Is there any way to raise context menu command's CanExcute while open the context menu. This need to be done in the context menu itself and here am not able to access the viewmodel.

Any idea on this?

    public static BaseCommand SaveCommand
    {
        get
        {
            if (saveCommand == null)
                saveCommand = new BaseCommand(OnSaveCommandClicked, OnSaveCommandCanExcute);

            return saveCommand;
        }
    }

where BaseCommand is derived from ICommand.

public class BaseCommand : ICommand
{
    private Predicate<object> _canExecute;
    private Action<object> _method;
    public event EventHandler CanExecuteChanged;

    public BaseCommand(Action<object> method)
        : this(method, null)
    {
    }

    public BaseCommand(Action<object> method, Predicate<object> canExecute)
    {
        _method = method;
        _canExecute = canExecute;
    }

    public bool CanExecute(object parameter)
    {
        if (_canExecute == null)
        {
            return true;
        }

        return _canExecute(parameter);
    }

    public void Execute(object parameter)
    {
        _method.Invoke(parameter);
    }

}

回答1:

Inside BaseCommand, replace the CanExecuteChanged to look like the following. And it will work the way you want it.

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

来源：https://stackoverflow.com/questions/18458509/raise-context-menu-commands-canexcute-while-open-the-context-menu