內建 BooleanToVisibilityConverter IValueConverter

布林值和可見性之間的轉換。獲取輸入的 bool 值並返回 Visibility 值。

注意：此轉換器已存在於 System.Windows.Controls 名稱空間中

public sealed class BooleanToVisibilityConverter : IValueConverter
{
    /// <summary>
    /// Convert bool or Nullable bool to Visibility
    /// </summary>
    /// <param name="value">bool or Nullable bool</param>
    /// <param name="targetType">Visibility</param>
    /// <param name="parameter">null</param>
    /// <param name="culture">null</param>
    /// <returns>Visible or Collapsed</returns>
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        bool bValue = false;
        if (value is bool)
        {
            bValue = (bool)value;
        }
        else if (value is Nullable<bool>)
        {
            Nullable<bool> tmp = (Nullable<bool>)value;
            bValue = tmp.HasValue ? tmp.Value : false;
        }
        return (bValue) ? Visibility.Visible : Visibility.Collapsed;
    }

    /// <summary>
    /// Convert Visibility to boolean
    /// </summary>
    /// <param name="value"></param>
    /// <param name="targetType"></param>
    /// <param name="parameter"></param>
    /// <param name="culture"></param>
    /// <returns></returns>
    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        if (value is Visibility)
        {
            return (Visibility)value == Visibility.Visible;
        }
        else
        {
            return false;
        }
    }
}

使用轉換器

1. 定義資源

<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>

3. 在繫結中使用它

<Button Visibility="{Binding AllowEditing, 
                             Converter={StaticResource BooleanToVisibilityConverter}}"/>