WPF 转换器属性

WPF Converter Property

提问by David Ward

I have a converter that in code I can set a property like:

我有一个转换器，我可以在代码中设置一个属性，如：

tabAssumptions.SetBinding(UIElement.VisibilityProperty, new Binding("CurrentPhase.IsWholeScheme") { Converter = new BoolToVisibilityConverter { Inverse = true } });

How can I set the Inverse property of the converter when used in XAML?

在 XAML 中使用时，如何设置转换器的 Inverse 属性？

回答by Phil

My BoolToVisibilityConverter is below. You can either use it as a resource:

我的 BoolToVisibilityConverter 如下。您可以将其用作资源：

 <converters:BoolToVisibilityConverter x:Key="FalseToHidden" 
     TrueValue="Visible" FalseValue="Hidden" />

or use it as a MarkupExtension inline in your XAML:

或将其用作 XAML 中的内联 MarkupExtension：

  Visibility="{Binding MyFlag, 
      Converter={vc:BoolToVisibilityConverter 
                 FalseValue=Collapsed, TrueValue=Visible}}"

C#

C＃

public class BoolToVisibilityConverter : BoolToValueConverter<Visibility>
{
    #region Constructors and Destructors

    public BoolToVisibilityConverter()
    {
        this.TrueValue = Visibility.Visible;
        this.FalseValue = Visibility.Collapsed;
    }

    #endregion
}

/// <summary>
/// Use as the base class for BoolToXXX style converters
/// </summary>
/// <typeparam name="T"></typeparam>    
public abstract class BoolToValueConverter<T> : MarkupExtension, IValueConverter
{
    #region Constructors and Destructors

    protected BoolToValueConverter()
    {
        this.TrueValue = default(T);
        this.FalseValue = default(T);
    }

    #endregion

    #region Public Properties

    public T FalseValue { get; set; }

    public T TrueValue { get; set; }

    #endregion

    #region Public Methods and Operators

    public object Convert(object value, Type targetType, 
                          object parameter, CultureInfo culture)
    {
        return System.Convert.ToBoolean(value) ? this.TrueValue : this.FalseValue;
    }

    // Override if necessary
    public virtual object ConvertBack(object value, Type targetType, 
                                      object parameter, CultureInfo culture)
    {
        return value.Equals(this.TrueValue);
    }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return this;
    }

    #endregion
}