WPF: Display a bool value as "Yes" / "No"

I have a bool value that I need to display as "Yes" or "No" in a TextBlock. I am trying to do this with a StringFormat, but my StringFormat is ignored and the TextBlock displays "True" or "False".

<TextBlock Text="{Binding Path=MyBoolValue, StringFormat='{}{0:Yes;;No}'}" />

Is there something wrong with my syntax, or is this type of StringFormat not supported?

I know I can use a ValueConverter to accomplish this, but the StringFormat solution seems more elegant (if it worked).

From stackoverflow

• Your solution with StringFormat can't work, because it's not a valid format string.

  I wrote a markup extension that would do what you want. You can use it like that :

  <TextBlock Text="{my:SwitchBinding MyBoolValue, Yes, No}" />
  

  Here the code for the markup extension :

  public class SwitchBindingExtension : Binding
  {
      public SwitchBindingExtension()
      {
          Initialize();
      }
  
      public SwitchBindingExtension(string path)
          : base(path)
      {
          Initialize();
      }
  
      public SwitchBindingExtension(string path, object valueIfTrue, object valueIfFalse)
          : base(path)
      {
          Initialize();
          this.ValueIfTrue = valueIfTrue;
          this.ValueIfFalse = valueIfFalse;
      }
  
      private void Initialize()
      {
          this.ValueIfTrue = Binding.DoNothing;
          this.ValueIfFalse = Binding.DoNothing;
          this.Converter = new SwitchConverter(this);
      }
  
      [ConstructorArgument("valueIfTrue")]
      public object ValueIfTrue { get; set; }
  
      [ConstructorArgument("valueIfFalse")]
      public object ValueIfFalse { get; set; }
  
      private class SwitchConverter : IValueConverter
      {
          public SwitchConverter(SwitchBindingExtension switchExtension)
          {
              _switch = switchExtension;
          }
  
          private SwitchBindingExtension _switch;
  
          #region IValueConverter Members
  
          public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
          {
              try
              {
                  bool b = System.Convert.ToBoolean(value);
                  return b ? _switch.ValueIfTrue : _switch.ValueIfFalse;
              }
              catch
              {
                  return DependencyProperty.UnsetValue;
              }
          }
  
          public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
          {
              return Binding.DoNothing;
          }
  
          #endregion
      }
  
  }
  

  John Myczek : You are right, that is not a valid format string for a bool value (it is valid for numeric values). I was testing the format string like this: string.Format("{0:Yes;;No}", 1), which returns "Yes", but string.Format("{0:Yes;;No}", true) returns "True". Thanks

• See the link below

  http://asimsajjad.blogspot.com/2010/02/ivalueconverter-interface.html

  Hope that will help.