Silverlight Expander.Header with additional button - data-binding

Question

When the Complete Survey button on the Expander.Header is clicked, I would like to Navigate to another page and pass along some information from the viewmodel. I have the expander working so that when its selected it expands, and the selecteditem property is properly bound and filled. However if I just click right to the button, the selecteditem does not change and is not even populated if its the first action. How can I trigger the selected item if the button control is pressed before the expander is selected? I would prefer an MVVM solution if possible. Thanks
<ListBox x:Name="SearchList"
Grid.Row="1"
Margin="5,0,5,0"
Grid.Column="0"
Background="Transparent"
BorderThickness="0"
BorderBrush="Transparent"
ItemsSource="{Binding Path=SearchResults}"
SelectedItem="{Binding Path=SelectedResult,Mode=TwoWay,Converter={StaticResource DebugConverter}}"
HorizontalContentAlignment="Stretch"
HorizontalAlignment="Stretch">
<ListBox.ItemTemplate>
<DataTemplate>
<toolkit:Expander>
<sb:BindingHelper.Binding>
<sb:RelativeSourceBinding TargetProperty="IsExpanded"
Path="IsSelected"
RelativeMode="FindAncestor"
AncestorType="ListBoxItem" BindingMode="TwoWay" />
</sb:BindingHelper.Binding>
<toolkit:Expander.Header>
<Grid Width="525">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="25" />
<ColumnDefinition Width="100" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<TextBlock Grid.Column="0"
Grid.Row="0"
Text="{Binding Path=PatientName}" />
<Button Grid.Column="2"
Grid.Row="0"
Content="Complete Survey">
<sb:BindingHelper.Binding>
<sb:RelativeSourceBinding Path="OpenSurveyCommand"
TargetProperty="Command"
RelativeMode="ParentDataContext" />
</sb:BindingHelper.Binding>
</Button>
</Grid>
</toolkit:Expander.Header>
<StackPanel>
<TextBlock Text="{Binding MRN,Converter={StaticResource StringLabelConverter},ConverterParameter=MRN}" />
<TextBlock Text="{Binding OriginalVisitNumber,Converter={StaticResource StringLabelConverter},ConverterParameter='Original Visit Number'}" />
<TextBlock Text="{Binding OriginalAdmitDate,Converter={StaticResource StringLabelConverter},ConverterParameter='Original Admit Date'}" />
<TextBlock Text="{Binding OriginalReason,Converter={StaticResource StringLabelConverter},ConverterParameter='Original Reason'}" />
<TextBlock Text="{Binding ReAdmitVisitNumber,Converter={StaticResource StringLabelConverter},ConverterParameter='ReAdmit Visit Number'}" />
<TextBlock Text="{Binding ReAdmitDate,Converter={StaticResource StringLabelConverter},ConverterParameter='Readmit Date'}" />
<TextBlock Text="{Binding ReAdmitReason,Converter={StaticResource StringLabelConverter},ConverterParameter='ReAdmit Reason'}" />
</StackPanel>
</toolkit:Expander>
</DataTemplate>
</ListBox.ItemTemplate>

Answer 1

I'm not familiar with the BindingHelper class you're using but if it's using the standard commanding in the background then I'd bind the command parameter to the "item".
That way you have access to the bound item in the commands executed event.

Answer 2

Using a collection of viewmodels with the button in the viewmodel solved this. No special magic other than the ObservableCollectionVM