Question

I have a ListBox on a form that is bound to an ObservableCollection of a custom type. Within each item there is a ComboBox bound to an enumeration type. When the window loads, all ComboBoxes are defaulted to a certain value. When I change the SelectedItem for any one (from the UI, not from code), all other ComboBoxes change to the same SelectedItem.

I’m not sure what I’ve done wrong, here is my current XAML that is handling this.

<Window.Resources>     <ObjectDataProvider x:Key='SyncOperationValues'                         MethodName='GetNames'                         ObjectType='{x:Type sys:Enum}'>         <ObjectDataProvider.MethodParameters>             <x:Type TypeName='local:SyncOperationEnum' />         </ObjectDataProvider.MethodParameters>     </ObjectDataProvider> ...     <DataTemplate x:Key='SyncListTemplate'>         <Grid Grid.Column='1' Grid.RowSpan='2' Margin='0,0,20,0' x:Name='olDetails'             DataContext='{Binding Path=OlContact}'>             <Grid.RowDefinitions>                 <RowDefinition />                 <RowDefinition />                 <RowDefinition />                 <RowDefinition />                 <RowDefinition />                 <RowDefinition />             <RowDefinition />             </Grid.RowDefinitions> ...             <ComboBox x:Name='SyncOp'                  Width='120' Height='19'                 Margin='4,0,10,0'                  IsSynchronizedWithCurrentItem='True'                  ItemsSource='{Binding Source={StaticResource SyncOperationValues}}'                              SelectedItem='{Binding Operation}'                              VerticalAlignment='Center' />  ... 

and the ListBox:

 <ListBox x:Name='SyncList'      ScrollViewer.HorizontalScrollBarVisibility='Hidden'      ItemContainerStyle='{StaticResource StretchedContainerStyle}'      ItemTemplate='{StaticResource SyncListTemplate}'>  ListBox> 

I have tried some different options, like binding to a CollectionView; however nothing seems to work. Can anyone point me to my mistake?

Thanks!

Answer 1

I have finally found a solution. I ended up writing a ValueConverter for the enumeration type. I’d been under the impression that this was not necessary, but for some reason it is, at least if the ComboBox is within another list (ListBox in my case) of some sort.

I did need to set the IsSynchronizedWithCurrentItem property to false as John M suggested, so thanks to John for that! Here is the converter code in case anyone else needs to do something like this.

[ValueConversion( typeof( SyncOperationEnum ), typeof( String ) )] public class SyncOperationConverter : IValueConverter {     #region IValueConverter Members      public object Convert( object value, Type targetType, object parameter, System.Globalization.CultureInfo culture ) {         if( value != null && value.GetType() == typeof( SyncOperationEnum ) )             return Enum.GetName( typeof( SyncOperationEnum ), value );          return null;     }      public object ConvertBack( object value, Type targetType, object parameter, System.Globalization.CultureInfo culture ) {         if( value != null && targetType == typeof( SyncOperationEnum ) )             foreach( object enumValue in Enum.GetValues( targetType ) )                 if( value.Equals( Enum.GetName( targetType, enumValue ) ) )                     return enumValue;          return null;     }      #endregion 

And my XAML now looks like this:

<Window.Resources>     <local:SyncOperationConverter x:Key='SyncConverter' />      <ObjectDataProvider x:Key='SyncOperationValues'                     MethodName='GetNames'                     ObjectType='{x:Type sys:Enum}'>         <ObjectDataProvider.MethodParameters>             <x:Type TypeName='local:SyncOperationEnum' />         </ObjectDataProvider.MethodParameters>     </ObjectDataProvider> ... <DataTemplate x:Key='SyncListTemplate'>     <Grid Grid.Column='1' Grid.RowSpan='2' Margin='0,0,20,0' x:Name='olDetails'         DataContext='{Binding Path=OlContact}'>         <Grid.RowDefinitions>             <RowDefinition />             <RowDefinition />             <RowDefinition />             <RowDefinition />             <RowDefinition />             <RowDefinition />         <RowDefinition />         </Grid.RowDefinitions> ...         <ComboBox x:Name='SyncOp'              Width='120' Height='19'             Margin='4,0,10,0'              IsSynchronizedWithCurrentItem='False'              ItemsSource='{Binding Source={StaticResource SyncOperationValues}}'             SelectedValue='{Binding Path=Operation,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged,Converter={StaticResource SyncConverter}}'             VerticalAlignment='Center' />