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MultiBinding to CheckBox.IsChecked not called converter

I have a custom combobox multiselectioncombobox, if you do,

thing - the choice depends on another collection. I tried to associate the ComboBox.IsChecked property with MultiBinding Converter, but the converter is not called.

<DataTemplate>
<StackPanel Orientation="Horizontal" x:Name="ItemStack" VirtualizingStackPanel.IsVirtualizing="False">
    <CheckBox x:Name="CheckBoxItem"
        Command="{Binding SelectItem, RelativeSource={RelativeSource AncestorType={x:Type MultiSelectionComboBox}}}"
        CommandParameter="{Binding Key}"
              >
        <CheckBox.IsChecked>
            <MultiBinding Converter="{StaticResource MultiSelectionCommandConverter}" Mode="OneWay">
                <Binding Path="Key"/>
                <Binding Path="SelectedItem"
                         RelativeSource="{RelativeSource AncestorType={x:Type MultiSelectionComboBox}}" />
            </MultiBinding>
        </CheckBox.IsChecked>
    </CheckBox>
    <TextBlock Text="{Binding DisplayText}"></TextBlock>
</StackPanel>
</DataTemplate>

and converter

public class MultiSelectionCommandConverter : IMultiValueConverter 
{      
    public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
    {   
            ///stuff to do...
    }

    public object[] ConvertBack(object values, Type[] targetTypes, object parameter, CultureInfo culture)
    {
        return null;
    }
}

any suggestions?

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1 answer

After testing the features, I found a job. However, I'm not quite sure why this might work, and the other won't.

I changed my xaml to pass the whole object instead of a property. So I liked the code,

<DataTemplate>
<StackPanel Orientation="Horizontal" x:Name="ItemStack" VirtualizingStackPanel.IsVirtualizing="False">
    <CheckBox x:Name="CheckBoxItem"
        Command="{Binding SelectItem, RelativeSource={RelativeSource AncestorType={x:Type MultiSelectionComboBox}}}"
        CommandParameter="{Binding Key}"
              >
        <CheckBox.IsChecked>
            <MultiBinding Converter="{StaticResource MultiSelectionCommandConverter}" Mode="OneWay">
                <Binding Path="Key"/>
                <Binding 
                         RelativeSource="{RelativeSource AncestorType={x:Type MultiSelectionComboBox}}" />
            </MultiBinding>
        </CheckBox.IsChecked>
    </CheckBox>
    <TextBlock Text="{Binding DisplayText}"></TextBlock>
</StackPanel>
</DataTemplate>

and converter

public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
{
    string key = (string)values[0];
    ObservableCollection<ListItem> selectedItems = (values[1] as MultiSelectionComboBox).SelectedItem;
    //do stuff
    return false;
}

This is definitely not the desired solution, but it will do until I find out another reason.

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