Well, this one’s kind of out of line. I faced this last night, searched all over I can but I barely found a concise solution on this one.

Before we get into the solution, we need to see the problem we’re talking about. Shouldn’t we?

I was working with the new Windows Phone 8 Map Control provided with the sdk that allows here maps to be used in your app and I needed a bunch of Pushpins to be loaded in the map. So, Windows Phone Toolkit came to the rescue. I hooked up the <MapExtensions.Children> and added by pushpins there binded from my viewmodel.

<Grid x:Name="ContentPanel" Grid.Row="1" Margin="12,0,12,0" >

            <maps:Map x:Name="MyMap" ZoomLevelChanged="MyMap_ZoomLevelChanged"  Loaded="MyMap_Loaded"   >

                <MapToolkit:MapExtensions.Children>

                    <MapToolkit:MapItemsControl Name="MapElements">
                        <MapToolkit:MapItemsControl.ItemTemplate>
                            <DataTemplate>
                                <MapToolkit:Pushpin Name="StopPushPin"  Style="{StaticResource MaximizedPushpin}"  Background="#B20000FF" Content="{Binding Name}" GeoCoordinate="{Binding Location}" Tap="Pushpin_Tap"  >
                                </MapToolkit:Pushpin>
                            </DataTemplate>
                        </MapToolkit:MapItemsControl.ItemTemplate>
                    </MapToolkit:MapItemsControl>
                    <MapToolkit:Pushpin Name="MyPushpin"  Content="I'm Here!" Background="#FF3CD303"  GeoCoordinate="{Binding MyLocation}" />
                </MapToolkit:MapExtensions.Children>

            </maps:Map>
        </Grid>

One could easily see here that I used a PushPin object as DataTemplate with a custom style attached. Lets check the style

<Style TargetType="MapToolkit:Pushpin" x:Key="MaximizedPushpin">

        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="MapToolkit:Pushpin">
                    <Grid x:Name="ContentGrid" FlowDirection="LeftToRight">

                        <toolkit:WrapPanel Orientation="Vertical">

                            <Grid x:Name="grid" Background="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Background}" HorizontalAlignment="Left"
                                   RenderTransformOrigin="0.5,0.5" Height="148" Width="225">

                                <Grid.RowDefinitions>
                                    <RowDefinition Height="0.4*"></RowDefinition>
                                    <RowDefinition Height="0.015*"></RowDefinition>
                                    <RowDefinition Height="0.25*"></RowDefinition>
                                    <RowDefinition Height="0.015*"></RowDefinition>
                                </Grid.RowDefinitions>

                                <TextBlock Margin="8,4,4,4"
                                           FlowDirection="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=FlowDirection}"
                                           Grid.Row="0" Text="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Content}"
                                           TextWrapping="Wrap" FontSize="30">

                                </TextBlock>

                                <Border Grid.Row="1" Background="#CC474444" Margin="0,0,-6,0" />
                                <Grid Grid.Row="2"   MinHeight="31" Background="#EEF9F9F9" Margin="0,0,-8,0"  >
                                    <codefun:RoundButton Orientation="Horizontal" Foreground="Black" Background="Transparent"
                                                         BorderBrush="Black" ImageSource="/Assets/pushpin.get.direction.png"
                                                         HorizontalAlignment="Left" VerticalAlignment="Center"
                                                         Margin="0,2,0,0"
                                                         >
                                    </codefun:RoundButton>
                                </Grid>
                                <Grid Grid.Row="3"   Background="#99474444" Margin="0,0,-6,0"/>
                            </Grid>

                            <Polygon Fill="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Background}"
                                     Points="0,0 29,0 0,29"
                                     Width="29"
                                     Height="29"
                                     HorizontalAlignment="Left"/>
                        </toolkit:WrapPanel>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
        <Setter Property="PositionOrigin" Value="0,1" />
        <Setter Property="Background" Value="Black" />
        <Setter Property="Foreground" Value="White" />
        <Setter Property="FontSize" Value="30" />
    </Style>

All I wanted to do is to bind Command Parameter of RoundButton and hook a RelayCommand in my viewmodel. As is an attached property in the Map control I had to use FindAncestor mode when I tried to bind Command parameter in RoundButton. But bad news is it’s not supported in Windows Phone. The only relative binding mode I have here is templatedparent and self.

And I started looking for a solution. Then this came to my eyes and I was really happy. So, I followed as per what was written in there and voila!

I binded the Command with CommandParameters the following way.

<codefun:RoundButton Orientation="Horizontal" Foreground="Black" Background="Transparent"
                                                         BorderBrush="Black" ImageSource="/Assets/pushpin.get.direction.png"
                                                         HorizontalAlignment="Left" VerticalAlignment="Center"
                                                         Margin="0,2,0,0"
                                                         CommandParameter="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=DataContext}"
                                                         >

                                        <BindHelper:BindingHelper.Binding>
                                            <BindHelper:RelativeSourceBinding
                                                Path="GetDirectionToPushPinCommand"
                                                TargetProperty="Command"
                                                RelativeMode="ParentDataContext"
                                                />

                                        </BindHelper:BindingHelper.Binding>
                                    </codefun:RoundButton>

A handy tool indeed!