WPF - 如果命令的 CanExecute 为假，如何隐藏菜单项? [英] WPF - how to hide menu item if command's CanExecute is false?

问题描述

By default menu items become disabled when its command cannot be executed (CanExecute = false). What is the easiest way to make the menu item visible/collapsed based on the CanExecute method?

解决方案

You can simply bind Visibility to IsEnabled (set to false on CanExecute == false). You still would need an IValueConverter to convert the bool to visible/collapsed.

    public class BooleanToCollapsedVisibilityConverter : IValueConverter
    {
        #region IValueConverter Members

        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            //reverse conversion (false=>Visible, true=>collapsed) on any given parameter
            bool input = (null == parameter) ? (bool)value : !((bool)value);
            return (input) ? Visibility.Visible : Visibility.Collapsed;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }

        #endregion
    }

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