OnIdiom<GridLength> throws an not implemented Exception (in GridLengthTypeConverter)

[inforithmics]

Description

OnIdiom throws an not implemented Exception (in GridLengthTypeConverter)

Following Xaml throws at runtime a NotSupported Exception

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition>
            <RowDefinition.Height>
                <OnIdiom x:TypeArguments="GridLength" Default="50" Desktop="100"/>
            </RowDefinition.Height>
        </RowDefinition>
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>
  
    <Label
        Text="Hello, World!" />
</Grid>

Steps to Reproduce

1. Create Maui App
2. Replace MainPage Code with this

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MauiApp3.MainPage">

    <ScrollView>
        <Grid>
            <Grid.RowDefinitions>
                <RowDefinition>
                    <RowDefinition.Height>
                        <OnIdiom x:TypeArguments="GridLength" Default="50" Desktop="100"/>
                    </RowDefinition.Height>
                </RowDefinition>
                <RowDefinition Height="*" />
            </Grid.RowDefinitions>
          
            <Label
                Text="Hello, World!" />
        </Grid>
    </ScrollView>

</ContentPage>

3. Start Application
4. Crashes with not supported exception

Link to public reproduction project repository

https://github.com/inforithmics/MauiOnIdiomGridLength

Version with bug

9.0.60 SR6

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

All

Did you find any workaround?

No

Similar issues: The workaround from there did not work
#10894

Relevant log output

[HarishwaranVijayakumar]

This issue has been verified in Visual Studio 17.14.0 Preview 2.0 with MAUI version 9.0.60. It can be reproduced on Windows platform.

[StephaneDelcroix]

oh, this is a fun one :) thanks

this uses Microsoft.Maui.GridLengthTypeConverter, and not Microsoft.Maui.CONTROLS.GridLengthTypeConverter, and fail

[cat0363]

I added Tablet and Phone to the XAML of this issue and checked the operation on Android and iOS. No exceptions occurred on Android and iOS, but the height specified in OnIdiom was not applied in the layout.