How do I invert BooleanToVisibilityConverter

Question

I m using a BooleanToVisibilityConverter in WPF to bind the Visibility property of a control to a Boolean  This works fine  but I d like one of the controls to hide if the boolean is true  and show if it s false

User · Answer

Rather than writing your own code   reinventing  consider using CalcBinding   Automatic two way convertion of bool expression to Visibility and back if target property has such type  description       lt Button Visibility   c Binding  IsChecked     gt        lt Button Visibility   c Binding IsChecked  FalseToVisibility Hidden     gt    CalcBinding is also quite useful for numerous other scenarios

User · Answer

using System  using System Globalization  using System Windows  using System Windows Data   public sealed class BooleanToVisibilityConverter   IValueConverter       public object Convert object value  Type targetType  object parameter  CultureInfo culture                var flag   false          if  value is bool                        flag    bool value                    else if  value is bool                         var nullable    bool  value              flag   nullable GetValueOrDefault                      if  parameter    null                        if  bool Parse  string parameter                                 flag    flag                                  if  flag                        return Visibility Visible                    else                       return Visibility Collapsed                       public object ConvertBack object value  Type targetType  object parameter  CultureInfo culture                var back     value is Visibility   amp  amp     Visibility value     Visibility Visible            if  parameter    null                        if   bool parameter                                back    back                                  return back            and then pass a true or false as the ConverterParameter          lt Grid Visibility gt                   lt Binding Path  IsYesNoButtonSetVisible  Converter   StaticResource booleanToVisibilityConverter   ConverterParameter  true   gt           lt  Grid Visibility gt

User · Answer

Instead of inverting  you can achieve the same goal by using a generic IValueConverter implementation that can convert a Boolean value to configurable target values for true and false  Below is one such implementation   public class BooleanConverter lt T gt    IValueConverter       public BooleanConverter T trueValue  T falseValue                True   trueValue          False   falseValue             public T True   get  set        public T False   get  set         public virtual object Convert object value  Type targetType  object parameter  CultureInfo culture                return value is bool  amp  amp    bool  value    True   False             public virtual object ConvertBack object value  Type targetType  object parameter  CultureInfo culture                return value is T  amp  amp  EqualityComparer lt T gt  Default Equals  T  value  True             Next  subclass it where T is Visibility   public sealed class BooleanToVisibilityConverter   BooleanConverter lt Visibility gt        public BooleanToVisibilityConverter              base Visibility Visible  Visibility Collapsed         Finally  this is how you could use BooleanToVisibilityConverter above in XAML and configure it to  for example  use Collapsed for true and Visible for false    lt Application Resources gt       lt app BooleanToVisibilityConverter          x Key  BooleanToVisibilityConverter           True  Collapsed           False  Visible    gt   lt  Application Resources gt    This inversion is useful when you want to bind to a Boolean property named IsHidden as opposed IsVisible

User · Answer

You can use QuickConverter   With QuickConverter you can write the converter logic inline with your BindingExpression  Here is an inverted BooleanToVisibility converter   Visibility   qc Binding    P   Visibility Visible   Visibility Collapsed   P  Binding Example      You can add QuickConverter via NuGet  Have a look at the documentation for setup  Link  https   quickconverter codeplex com

User · Answer

I was looking for a more general answer  but could not find it  I wrote a converter that might help others   It is based on the fact that we need to distinguish six different cases    True  2  Visible    False 2 Hidden True  2  Visible    False 2 Collapsed True  2  Hidden     False 2 Visible True  2  Collapsed  False 2 Visible True  2  Hidden     False 2 Collapsed True  2  Collapsed  False 2 Hidden   Here is my implementation for the first 4 cases    ValueConversion typeof bool   typeof Visibility    public class BooleanToVisibilityConverter   IValueConverter       enum Types                    lt summary gt              True to Visible  False to Collapsed              lt  summary gt          t2v f2c               lt summary gt              True to Visible  False to Hidden              lt  summary gt          t2v f2h               lt summary gt              True to Collapsed  False to Visible              lt  summary gt          t2c f2v               lt summary gt              True to Hidden  False to Visible              lt  summary gt          t2h f2v            public object Convert object value  Type targetType                            object parameter  CultureInfo culture                var b    bool value          string p    string parameter          var type    Types Enum Parse typeof Types    string parameter           switch  type                        case Types t2v f2c                  return b   Visibility Visible   Visibility Collapsed               case Types t2v f2h                  return b   Visibility Visible   Visibility Hidden               case Types t2c f2v                  return b   Visibility Collapsed   Visibility Visible               case Types t2h f2v                  return b   Visibility Hidden   Visibility Visible                     throw new NotImplementedException               public object ConvertBack object value  Type targetType          object parameter  CultureInfo culture                var v    Visibility value          string p    string parameter          var type    Types Enum Parse typeof Types    string parameter           switch  type                        case Types t2v f2c                  if  v    Visibility Visible                      return true                  else if  v    Visibility Collapsed                      return false                  break              case Types t2v f2h                  if  v    Visibility Visible                      return true                  else if  v    Visibility Hidden                      return false                  break              case Types t2c f2v                  if  v    Visibility Visible                      return false                  else if  v    Visibility Collapsed                      return true                  break              case Types t2h f2v                  if  v    Visibility Visible                      return false                  else if  v    Visibility Hidden                      return true                  break                    throw new InvalidOperationException              example   Visibility   Binding HasItems  Converter  StaticResource BooleanToVisibilityConverter   ConverterParameter  t2v f2c      I think the parameters are easy to remember   Hope it helps somebody

User · Answer

Or the real lazy mans way  just make use of what is there already and flip it   public class InverseBooleanToVisibilityConverter   IValueConverter       private BooleanToVisibilityConverter  converter   new BooleanToVisibilityConverter         public object Convert object value  Type targetType  object parameter  System Globalization CultureInfo culture                var result    converter Convert value  targetType  parameter  culture  as Visibility           return result    Visibility Collapsed   Visibility Visible   Visibility Collapsed             public object ConvertBack object value  Type targetType  object parameter  System Globalization CultureInfo culture                var result    converter ConvertBack value  targetType  parameter  culture  as bool           return result    true   false   true

User · Answer

I know this is dated  but  you don t need to re-implement anything   What I did was to negate the value on the property like this    lt  -- XAML code -- gt   lt StackPanel Name  x   Visibility   Binding    Path Specials  ElementName MyWindow  Converter  StaticResource BooleanToVisibilityConverter    gt  lt  StackPanel gt       lt StackPanel Name  y   Visibility   Binding Path NotSpecials  ElementName MyWindow  Converter  StaticResource BooleanToVisibilityConverter    gt  lt  StackPanel gt                    Code behind public bool Specials       get   return  bool  GetValue SpecialsProperty         set               NotSpecials   value           SetValue SpecialsProperty  value            public bool NotSpecials       get   return  bool  GetValue NotSpecialsProperty         set   SetValue NotSpecialsProperty  value         And it works just fine   Am I missing something

User · Answer

Convert everything to everything  bool string enum etc    public class EverythingConverterValue       public object ConditionValue   get  set        public object ResultValue   get  set       public class EverythingConverterList   List lt EverythingConverterValue gt        public class EverythingConverter   IValueConverter       public EverythingConverterList Conditions   get  set      new EverythingConverterList         public object NullResultValue   get  set        public object NullBackValue   get  set         public object Convert object value  Type targetType          object parameter  CultureInfo culture                return Conditions Where x   gt  x ConditionValue Equals value   Select x   gt  x ResultValue  FirstOrDefault      NullResultValue            public object ConvertBack object value  Type targetType          object parameter  CultureInfo culture                return Conditions Where x   gt  x ResultValue Equals value   Select x   gt  x ConditionValue  FirstOrDefault      NullBackValue            XAML Examples    lt ResourceDictionary xmlns  http   schemas microsoft com winfx 2006 xaml presentation                  xmlns x  http   schemas microsoft com winfx 2006 xaml                  xmlns conv  clr-namespace MvvmGo Converters assembly MvvmGo WindowsWPF                  xmlns sys  clr-namespace System assembly mscorlib  gt    lt conv EverythingConverter x Key  BooleanToVisibilityConverter  gt       lt conv EverythingConverter Conditions gt           lt conv EverythingConverterValue ResultValue   x Static Visibility Visible   gt               lt conv EverythingConverterValue ConditionValue gt                   lt sys Boolean gt True lt  sys Boolean gt               lt  conv EverythingConverterValue ConditionValue gt           lt  conv EverythingConverterValue gt           lt conv EverythingConverterValue ResultValue   x Static Visibility Collapsed   gt               lt conv EverythingConverterValue ConditionValue gt                   lt sys Boolean gt False lt  sys Boolean gt               lt  conv EverythingConverterValue ConditionValue gt           lt  conv EverythingConverterValue gt       lt  conv EverythingConverter Conditions gt    lt  conv EverythingConverter gt    lt conv EverythingConverter x Key  InvertBooleanToVisibilityConverter  gt       lt conv EverythingConverter Conditions gt           lt conv EverythingConverterValue ResultValue   x Static Visibility Visible   gt               lt conv EverythingConverterValue ConditionValue gt                   lt sys Boolean gt False lt  sys Boolean gt               lt  conv EverythingConverterValue ConditionValue gt           lt  conv EverythingConverterValue gt           lt conv EverythingConverterValue ResultValue   x Static Visibility Collapsed   gt               lt conv EverythingConverterValue ConditionValue gt                   lt sys Boolean gt True lt  sys Boolean gt               lt  conv EverythingConverterValue ConditionValue gt           lt  conv EverythingConverterValue gt       lt  conv EverythingConverter Conditions gt   lt  conv EverythingConverter gt    lt conv EverythingConverter x Key  MarriedConverter  NullResultValue  Single  gt       lt conv EverythingConverter Conditions gt           lt conv EverythingConverterValue ResultValue  Married  gt               lt conv EverythingConverterValue ConditionValue gt                   lt sys Boolean gt True lt  sys Boolean gt               lt  conv EverythingConverterValue ConditionValue gt           lt  conv EverythingConverterValue gt           lt conv EverythingConverterValue ResultValue  Single  gt               lt conv EverythingConverterValue ConditionValue gt                   lt sys Boolean gt False lt  sys Boolean gt               lt  conv EverythingConverterValue ConditionValue gt           lt  conv EverythingConverterValue gt       lt  conv EverythingConverter Conditions gt       lt conv EverythingConverter NullBackValue gt           lt sys Boolean gt False lt  sys Boolean gt       lt  conv EverythingConverter NullBackValue gt   lt  conv EverythingConverter gt

User · Answer

Here s one I wrote and use a lot  It uses a boolean converter parameter that indicates whether or not to invert the value and then uses XOR to perform the negation    ValueConversion typeof bool   typeof System Windows Visibility    public class BooleanVisibilityConverter   IValueConverter       System Windows Visibility  visibilityWhenFalse   System Windows Visibility Collapsed            lt summary gt          Gets or sets the  lt see cref  System Windows Visibility   gt  value to use when the value is false  Defaults to collapsed           lt  summary gt      public System Windows Visibility VisibilityWhenFalse               get   return  visibilityWhenFalse            set    visibilityWhenFalse   value               public object Convert object value  Type targetType  object parameter  CultureInfo culture                bool negateValue          Boolean TryParse parameter as string  out negateValue            bool val   negateValue   System Convert ToBoolean value     Negate the value when negateValue is true using XOR         return val   System Windows Visibility Visible    visibilityWhenFalse             public object ConvertBack object value  Type targetType  object parameter  CultureInfo culture                bool negateValue          Boolean TryParse parameter as string  out negateValue            if   System Windows Visibility value    System Windows Visibility Visible              return true   negateValue          else             return false   negateValue            Here s an XOR truth table for reference             XOR         x  y  XOR         ---------         0  0  0         0  1  1         1  0  1         1  1  0

User · Answer

One more way to Bind ViewModel Boolean Value  IsButtonVisible  with xaml Control Visibility Property  No coding  No converting  just styling    lt Style TargetType  x Type Button  x Key  HideShow  gt      lt Style Triggers gt         lt DataTrigger Binding   Binding IsButtonVisible   Value  False  gt             lt Setter Property  Visibility  Value  Hidden   gt         lt  DataTrigger gt      lt  Style Triggers gt   lt  Style gt    lt Button Style   StaticResource HideShow   gt Hello lt  Button gt

User · Answer

A simple one way version which can be used like this   Visibility   Binding IsHidden  Converter  x Static Ui Converters BooleanToVisibility   ConverterParameter true    can be implemented like this   public class BooleanToVisibilityConverter   IValueConverter     public object Convert object value  Type targetType  object parameter  CultureInfo culture          var invert   false       if  parameter    null              invert   Boolean Parse parameter ToString                var booleanValue    bool  value       return   booleanValue  amp  amp   invert       booleanValue  amp  amp  invert            Visibility Visible   Visibility Collapsed         public object ConvertBack object value  Type targetType  object parameter  CultureInfo culture          throw new NotImplementedException

User · Answer

If you don t like writing custom converter  you could use data triggers to solve this    lt Style Triggers gt           lt DataTrigger Binding   Binding YourBinaryOption   Value  True  gt                    lt Setter Property  Visibility  Value  Visible    gt           lt  DataTrigger gt           lt DataTrigger Binding   Binding YourBinaryOption   Value  False  gt                    lt Setter Property  Visibility  Value  Collapsed    gt           lt  DataTrigger gt   lt  Style Triggers gt

User · Answer

Write your own convert   public class ReverseBooleanToVisibilityConverter   IValueConverter       public object Convert object value  Type targetType  object parameter  CultureInfo culture                 your converter code here

User · Answer

I just did a post on this   I used a similar idea as Michael Hohlios did  Only  I used Properties instead of using the  object parameter    Binding Visibility to a bool value in WPF Using Properties makes it more readable  in my opinion    lt local BoolToVisibleOrHidden x Key  BoolToVisConverter  Collapse  True  Reverse  True    gt

User · Answer

There s also the WPF Converters project on Codeplex  In their documentation they say you can use their MapConverter to convert from Visibility enumeration to bool   lt Label gt       lt Label Visible gt           lt Binding Path  IsVisible  gt               lt Binding Converter gt                   lt con MapConverter gt                       lt con Mapping From  True  To   x Static Visibility Visible    gt                       lt con Mapping From  False  To   x Static Visibility Hidden    gt                   lt  con MapConverter gt               lt  Binding Converter gt           lt  Binding gt       lt  Label Visible gt   lt  Label gt

User · Answer

Write your own is the best solution for now  Here is an example of a Converter that can do both way Normal and Inverted  If you have any problems with this just ask    ValueConversion typeof bool   typeof Visibility    public class InvertableBooleanToVisibilityConverter   IValueConverter       enum Parameters               Normal  Inverted            public object Convert object value  Type targetType                            object parameter  CultureInfo culture                var boolValue    bool value          var direction    Parameters Enum Parse typeof Parameters    string parameter            if direction    Parameters Inverted              return  boolValue  Visibility Visible   Visibility Collapsed           return boolValue  Visibility Visible   Visibility Collapsed             public object ConvertBack object value  Type targetType          object parameter  CultureInfo culture                return null               lt UserControl Resources gt     lt Converters InvertableBooleanToVisibilityConverter x Key   Converter   gt   lt  UserControl Resources gt    lt Button Visibility   Binding IsRunning  Converter  StaticResource  Converter   ConverterParameter Inverted   gt Start lt  Button gt

User · Answer

Implement your own implementation of IValueConverter   A sample implementation is at   http   msdn microsoft com en-us library system windows data ivalueconverter aspx  In your Convert method  have it return the values you d like instead of the defaults

[.net] How do I invert BooleanToVisibilityConverter?

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