Execute a Command on Custom Marker tap

[James Lavery]

I've got custom markers displaying on an OpenStreetMap, with the following XAML:

                                    <maps:SfMaps Grid.Row="1"

                                                 Grid.Column="0"

                                                 Grid.ColumnSpan="2"

                                                 x:Name="Map"

                                                 MinZoom="11"

                                                 EnableZooming="true"

                                                 ZoomLevel="10"

                                                 MaxZoom="13">

                                        <maps:SfMaps.Layers>

                                            <maps:ImageryLayer

                                                x:Name="OpenStreetMap"

                                                Markers="{Binding MapStations}"

                                                GeoCoordinates="50.8088760375977,-1.18579387664795">

                                                <maps:ShapeFileLayer.MarkerTemplate>

                                                    <DataTemplate>

                                                        <StackLayout>

                                                            <controls:WindIndicator

                                                                WidthRequest="70"

                                                                HeightRequest="70"

                                                                WindForce="{Binding Station.LatestReading.WindForce}"

                                                                WindDirection="{Binding Station.LatestReading.WindDirectionAsInt}">

                                                            </controls:WindIndicator>

                                                        </StackLayout>

                                                    </DataTemplate>

                                                </maps:ShapeFileLayer.MarkerTemplate>

                                                </maps:ImageryLayer>

                                        </maps:SfMaps.Layers>

                                    </maps:SfMaps>

The WindIndicator control is a custom control which uses SkiaSharp to draw wind direction and strength.

I want to invoke a Command when the WindIndicator is tapped - how can I do this? I've tried adding a GestureRecognizer to the StackLayout in the DataTemplate, but I think the tap behaviour of the SfMaps control itself is intercepting the tap.

[Rachel A]

Hi James, 

 

Greetings from Syncfusion. 

 

We have analyzed that your requirement is to perform an action when marker is tapped you can use MarkerSelected event in imagery layer. You can refer the below documentation link for more information. 

 

https://help.syncfusion.com/xamarin/sfmaps/markers#events 

 

Also, we can use behavior to invoke the command for specific events using the below link. 

 

https://docs.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/behaviors/reusable/event-to-command-behavior 

 

Please let us know if you have any concerns. 

 

Thanks, 

Rachel. 

[James Lavery]

Thank you for the proposed solution.

I have got the MarkerSelected event working, but unfortunately an ImageryLayer does not have a Behaviors property, so I cannot add an EventToCommandBehavior to the ImageryLayer.

Do you have a suggested workaround?

Regards,

James

[Rachel A]

Hi James, 

 

Sorry for the inconvenience. 

 

Currently there is no support to achieve it using behaviors, but we can invoke the command from the selected event as explained in the below link 

 

https://dotnetdevaddict.co.za/2017/07/13/turning-events-into-commands/  

 

Please find the snippet below 

 

[XAML]: 

… 

<maps:SfMaps.Layers> 

  <maps:ImageryLayer x:Name="OpenStreetMap" 

                     GeoCoordinates="50.8088760375977,-1.18579387664795" 

                     MarkerSelected="Layer_MarkerSelected"> 

    <maps:ImageryLayer.Markers> 

      <local:CustomMarker  Latitude="50.8088760375977" Longitude= "-1.18579387664795"  /> 

    </maps:ImageryLayer.Markers> 

    … 

</maps:SfMaps.Layers> 

… 

 

[C#]: 

… 

public partial class MainPage : ContentPage 

{ 

    public MainPage() 

    { 

        InitializeComponent(); 

        this.BindingContext = new ColorMappingsViewModel(); 

    } 

 

    private void Layer_MarkerSelected(object sender, MarkerSelectedEventArgs e) 

    { 

        var colorMappingsViewModel = (ColorMappingsViewModel)BindingContext; 

 

        if (colorMappingsViewModel.TapCommand.CanExecute(e)) 

        { 

            colorMappingsViewModel.TapCommand.Execute(e); 

        } 

    } 

} 

… 

 

Please find the sample from the below link. 

https://www.syncfusion.com/downloads/support/forum/147367/ze/mapssample-1371457090  

 

Regards, 

Rachel. 

[James Lavery]

That's how I've worked around it without using Behaviors. Thank you for confirming that my approach is the only/best one.

Regards,

James

[Vignesh Ramesh]

Hi James, 

Thanks for your feedback and we are glad that on resolving your problem. 

Regards, 

Vignesh.