Como se fazer uma caixa de seleção no Windows Phone

Question

Estou criando uma tela que ao ser aberta terá que carregar algumas informações no banco em uma caixa de seleção  para a escolha do usuário, já tentei utilizar scrollviewer com listbo e textblock mas não funcionou como eu tenho que fazer

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0">
            <TextBlock Height="30" HorizontalAlignment="Left" Margin="23,25,0,0" Name="textBlock1" Text="Assunto:" VerticalAlignment="Top" />
            <TextBox Height="69" HorizontalAlignment="Left" Margin="112,6,0,0" Name="textAssunto" Text="" VerticalAlignment="Top" Width="338" />
            <TextBlock Height="30" HorizontalAlignment="Left" Margin="23,100,0,0" Name="textBlock2" Text="Categoria:" VerticalAlignment="Top" />
            <ScrollViewer Height="48" HorizontalAlignment="Left" Margin="126,91,0,0" Name="scrollCategoria" VerticalAlignment="Top" Width="313">
                <ListBox x:Name="listCategoria">
                    <ListBox.ItemTemplate>
                        <DataTemplate>
                            <TextBlock Text="{Binding Name}" />
                        </DataTemplate>
                    </ListBox.ItemTemplate>
                </ListBox>
            </ScrollViewer>
            
            <TextBlock Height="30" HorizontalAlignment="Left" Margin="23,158,0,0" Name="textBlock3" Text="Contexto:" VerticalAlignment="Top" />
            <TextBox Height="342" HorizontalAlignment="Left" Margin="23,194,0,0" Name="textContexto" Text="" VerticalAlignment="Top" Width="416" />
        
            <Button Content="Solicitar" Height="72" HorizontalAlignment="Left" Margin="126,566,0,0" Name="btnSolicitar" VerticalAlignment="Top" Width="200" Click="btnSolicitar_Click" />

        </Grid>

<grid grid.row="1" margin="12,0,12,0" x:name="ContentPanel"><textblock height="30" horizontalalignment="Left" margin="23,25,0,0" name="textBlock1" text="Assunto:" verticalalignment="Top"><textbox height="69" horizontalalignment="Left" margin="112,6,0,0" name="textAssunto" text="" verticalalignment="Top" width="338"><textblock height="30" horizontalalignment="Left" margin="23,100,0,0" name="textBlock2" text="Categoria:" verticalalignment="Top"> <scrollviewer height="48" horizontalalignment="Left" margin="126,91,0,0" name="scrollCategoria" verticalalignment="Top" width="313"> <listbox x:name="listCategoria"> <listbox.itemtemplate> <datatemplate></datatemplate></listbox.itemtemplate></listbox> <textblock height="30" horizontalalignment="Left" margin="23,158,0,0" name="textBlock3" text="Contexto:" verticalalignment="Top"></textblock></scrollviewer></textblock></textbox></textblock></grid>