WPF control local:InverseBooleanConverter value is not a valid MarkupExtension expression

Question

I am getting this error: local:InverseBooleanConverter value is not a valid MarkupExtension expression. Cannot resolve InverseBooleanConverter

So My I my class InverseBooleanConverter is in the same namespace at my control and I do have this:

xmlns:local="clr-namespace:SpriteControl"

I looked up what a MarkupExtension expression and I saw a few of them, but I do not know with one I should use.

I tried x:Reference but is did not work here is my code:

  <Button Command="{Binding SP1Btn}" Content="Apply New Value" FontSize="12" IsEnabled="{Binding Path=IsReadOnly,ElementName=OPTextBox, Converter={Reference: InverseBooleanConverter}}" />

I also did try using local but that did not work.

I tried building the solution without any errors and then try the line and that did not work.

namespace SpriteControl
{

public class InverseBooleanConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
    {
        try
        {
            bool testValue = (bool)value;
            return !testValue; // or do whatever you need with this boolean
        }
        catch { return true; } // or false
    }

    public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
    {
        return Convert(value, targetType, parameter, culture);
    }
}

}

Answer 1

In order to get your Converter to work you need to declare it in your xaml, like so:

<UserControl or Window ...
    xmlns:local="clr-namespace:SpriteControl">
    <UserControl.Resources>
        <local:InverseBooleanConverter x:Key="InverseBooleanConverter"/>
    <UserControl.Resources/>
<Button Command="{Binding SP1Btn}" Content="Apply New Value" FontSize="12" IsEnabled="{Binding Path=IsReadOnly,ElementName=OPTextBox, Converter={StaticResource InverseBooleanConverter}}" />  

Your command should implement ICommand interface and it should have can execute associated with it. This will handle IsEnabled property on the button for you.