WPF Property Data binding to negate the property

Question

Is there any way to change the value of property at runtime in WPF data binding. Let's say my TextBox is bind to a IsAdmin property. Is there anyway I can change that property value in XAML to be !IsAdmin.

I just want to negate the property so Valueconverter might be an overkill!

NOTE: Without using ValueConverter

Answer 1

You can use an IValueConverter.

[ValueConversion(typeof(bool), typeof(bool))] public class InvertBooleanConverter : IValueConverter {     public object Convert(object value, Type targetType, object parameter, CultureInfo culture)     {         bool original = (bool)value;         return !original;     }      public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)     {         bool original = (bool)value;         return !original;     } } 

Then you'd setup your binding like:

<TextBlock Text="{Binding Path=IsAdmin, Converter={StaticResource boolConvert}}" /> 

Add a resource (usually in your UserControl/Window) like so:

<local:InvertBooleanConverter  x:Key="boolConvert"/> 

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Edit in response to comment:

If you want to avoid a value converter for some reason (although I feel that it's the most appropriate place), you can do the conversion directly in your ViewModel. Just add a property like:

public bool IsRegularUser {      get { return !this.IsAdmin; } } 

If you do this, however, make sure your IsAdmin property setter also raises a PropertyChanged event for "IsRegularUser" as well as "IsAdmin", so the UI updates accordingly.