EnumToBoolConverter - No property, BindableProperty, or event found for "TrueValues", or mismatching type between value and property.

[BioTurboNick]

I believe I followed the documentation correctly, but I'm getting an error:

No property, BindableProperty, or event found for "TrueValues", or mismatching type between value and property.

The code:

<toolkit:EnumToBoolConverter x:Key="inCountingMode">
    <toolkit:EnumToBoolConverter.TrueValues>
        <e:MeasurementPageMode>Counting</e:MeasurementPageMode>
    </toolkit:EnumToBoolConverter.TrueValues>
</toolkit:EnumToBoolConverter>

public enum MeasurementPageMode
{
    Counting,
    Editing,
    Results
}

What did I do wrong?

[bijington]

The issue here is that you are assigning a single value into the TrueValues property which cannot implicitly be converted to the underlying type of IList. To workaround that issue you can add a second value into the TrueValues property as below:

<toolkit:EnumToBoolConverter x:Key="inCountingMode">
    <toolkit:EnumToBoolConverter.TrueValues>
        <e:MeasurementPageMode>Counting</e:MeasurementPageMode>
        <e:MeasurementPageMode>Counting</e:MeasurementPageMode>
    </toolkit:EnumToBoolConverter.TrueValues>
</toolkit:EnumToBoolConverter>

It's not ideal but the compiler will be able to convert that to the desired type. I believe can could create a list in XAML but it would be more verbose than this workaround.

[danielancines]

I've made some tests and the problem apears to be with Enum type, with strings and int the error don't occur.

[bijington]

oh interesting! I suspect this is because TrueValues is of type IList<Enum> and not the explicit type of IList< MeasurementPageMode> from the original example. If that is the case we could possibly look at:

1. Allowing the developer to provide the generic type

This would make the types match and possibly solve the issue.

<toolkit:EnumToBoolConverter x:Key="inCountingMode" x:TypeArguments="e:MeasurementPageMode">
    <toolkit:EnumToBoolConverter.TrueValues>
        <e:MeasurementPageMode>Counting</e:MeasurementPageMode>
        <e:MeasurementPageMode>Counting</e:MeasurementPageMode>
    </toolkit:EnumToBoolConverter.TrueValues>
</toolkit:EnumToBoolConverter>

2. Investigate whether a TypeConverter could solve the issue here.

[danielancines]

I've been running another tests and I notice that, if you try to instanciate a IList of Enum property using List of MeasurementPageMode it'll not work, only if you add the value of MeasurementPageMode, like MeasurementPageMode.Counting. Because of this behavior your workaround works.

[BioTurboNick]

It seems like there might be a similar problem with CompareConverter? The docs show you can just put an integer in the XAML, but I'm getting an error. And I see the property in the class is IComparable?

[bijington]

@BioTurboNick what error are you getting? You should be able to use an integer or double, etc. in XAML as per this:

https://github.com/CommunityToolkit/Maui/blob/main/samples/CommunityToolkit.Maui.Sample/Pages/Converters/CompareConverterPage.xaml

[CliffAgius]

Closed as answered