Binding ConverterParameter

Question

Is there a way I could do this in a Style    lt Style TargetType  FrameworkElement  gt       lt Setter Property  Visibility  gt           lt Setter Value gt               lt Binding Path  Tag                  RelativeSource   RelativeSource AncestorType UserControl                   Converter   StaticResource AccessLevelToVisibilityConverter                   ConverterParameter   Binding RelativeSource  RelativeSource Mode Self   Path Tag     gt                                   lt  Setter Value gt       lt  Setter gt   lt  Style gt    I simply need to send the Tag of top-level parent and the Tag of control itself to my converter class

User · Accepted Answer

The ConverterParameter property can not be bound because it is not a dependency property   Since Binding is not derived from DependencyObject none of its properties can be dependency properties  As a consequence  a Binding can never be the target object of another Binding   There is however an alternative solution  You could use a MultiBinding with a multi-value converter instead of a normal Binding    lt Style TargetType  FrameworkElement  gt       lt Setter Property  Visibility  gt           lt Setter Value gt               lt MultiBinding Converter   StaticResource AccessLevelToVisibilityConverter   gt                   lt Binding Path  Tag  RelativeSource   RelativeSource Mode FindAncestor                                                       AncestorType UserControl    gt                   lt Binding Path  Tag  RelativeSource   RelativeSource Mode Self    gt               lt  MultiBinding gt           lt  Setter Value gt       lt  Setter gt   lt  Style gt    The multi-value converter gets an array of source values as input   public class AccessLevelToVisibilityConverter   IMultiValueConverter       public object Convert          object   values  Type targetType  object parameter  CultureInfo culture                return values All v   gt   v is bool  amp  amp   bool v                 Visibility Visible               Visibility Hidden             public object   ConvertBack          object value  Type   targetTypes  object parameter  CultureInfo culture                throw new NotSupportedException

User · Answer

No  unfortunately this will not be possible because ConverterParameter is not a DependencyProperty so you won t be able to use bindings  But perhaps you could cheat and use a MultiBinding with IMultiValueConverter to pass in the 2 Tag properties

User · Answer

There is also an alternative way to use MarkupExtension in order to use Binding for a ConverterParameter  With this solution you can still use the default IValueConverter instead of the IMultiValueConverter because the ConverterParameter is passed into the IValueConverter just like you expected in your first sample    Here is my reusable MarkupExtension        lt summary gt           lt example gt               lt TextBox gt                   lt TextBox Text gt                       lt wpfAdditions ConverterBindableParameter Binding   Binding FirstName                           Converter   StaticResource TestValueConverter                           ConverterParameterBinding   Binding ConcatSign     gt                   lt  TextBox Text gt               lt  TextBox gt           lt  example gt       lt  summary gt     ContentProperty nameof Binding    public class ConverterBindableParameter   MarkupExtension        region Public Properties      public Binding Binding   get  set        public BindingMode Mode   get  set        public IValueConverter Converter   get  set        public Binding ConverterParameter   get  set          endregion      public ConverterBindableParameter                public ConverterBindableParameter string path                Binding   new Binding path              public ConverterBindableParameter Binding binding                Binding   binding              region Overridden Methods      public override object ProvideValue IServiceProvider serviceProvider                var multiBinding   new MultiBinding            Binding Mode   Mode          multiBinding Bindings Add Binding           if  ConverterParameter    null                        ConverterParameter Mode   BindingMode OneWay              multiBinding Bindings Add ConverterParameter                     var adapter   new MultiValueConverterAdapter                       Converter   Converter                    multiBinding Converter   adapter          return multiBinding ProvideValue serviceProvider               endregion       ContentProperty nameof Converter        private class MultiValueConverterAdapter   IMultiValueConverter               public IValueConverter Converter   get  set             private object lastParameter           public object Convert object   values  Type targetType  object parameter  CultureInfo culture                        if  Converter    null  return values 0      Required for VS design-time             if  values Length  gt  1  lastParameter   values 1               return Converter Convert values 0   targetType  lastParameter  culture                      public object   ConvertBack object value  Type   targetTypes  object parameter  CultureInfo culture                        if  Converter    null  return new object     value       Required for VS design-time              return new object     Converter ConvertBack value  targetTypes 0   lastParameter  culture                         With this MarkupExtension in your code base you can simply bind the ConverterParameter the following way    lt Style TargetType  FrameworkElement  gt   lt Setter Property  Visibility  gt       lt Setter Value gt        lt wpfAdditions ConverterBindableParameter Binding   Binding Tag  RelativeSource  RelativeSource Mode FindAncestor  AncestorType  x Type UserControl                    Converter   StaticResource AccessLevelToVisibilityConverter                    ConverterParameterBinding   Binding RelativeSource  RelativeSource Mode Self   Path Tag     gt                 lt  Setter Value gt   lt  Setter gt      Which looks almost like your initial proposal

[wpf] Binding ConverterParameter

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