[Enhancement] PinsSource on Forms.Map

[hartez]

Rationale

Forms.Maps does not currently have a way to bind a list of Pins on a Map.

Implementation

Add a bindable property PinsSource to Map:

public static readonly BindableProperty PinsSourceProperty =
	BindableProperty.Create(nameof(PinsSource), typeof(IList), typeof(Map), default(IList));

public IList PinsSource
{
	get { return (IList)GetValue(PinsSourceProperty); }
	set { SetValue(PinsSourceProperty, value); }
}	

And a PinTemplate property:

public static readonly BindableProperty PinTemplateProperty = BindableProperty.Create("PinTemplate", typeof(DataTemplate), typeof(Map);

public DataTemplate PinTemplate
{
	get { return (DataTemplate)GetValue(PinTemplateProperty); }
	set { SetValue(PinTemplateProperty, value); }
}

The PinTemplate is responsible for converting the objects in the PinsSource into Xamarin.Forms.Maps.Pin objects.

Setting the PinsSource will clear out any existing pins and update the pin collection to match the source.

Backward Compatibility

This is a new property, so there should not be any backward compatibility issues.

Difficulty: Moderate

[jassmith]

Should we maybe use a DataTemplate + IEnumable instead to avoid the inevitable issue of people then being forced to use a Forms type in their ViewModel to make this work?

Also the behavior of what this does to the Pins collection needs to be well defined.

[davidortinau]

@jsuarezruiz this is for you

[jassmith]

Hey @jsuarezruiz, you still working on this? If not we can move it back to the ready for work column

[jsuarezruiz]

@jassmith I focused earlier on the CornerRadius of the BoxView and I'm still working on it. At the moment I have a version for Android, iOS and UWP. I need to implement in GTK, macOS and WPF. On the other hand, in the current implementation I use ViewCell in the DataTemplate and I'm not sure if we wants to avoid or there's no problem.
I try to have it as soon as possible, although if someone from the Xamarin.Forms Team or the community wants to continue/review it, I share what I have and I take another one.

[jassmith]

No rush, Im just doing check ins to make sure we don't lose track of things or get people duplicating efforts, if you are still working on it super :)

If you want to post up your partial work so far, great :) We would take the implementation on Android/iOS/UWP without waiting on the others.

[PureWeen]

If you want to post up your partial work so far, great :) We would take the implementation on Android/iOS/UWP without waiting on the others.

@jsuarezruiz

thoughts?

[samhouts]

@jsuarezruiz Any progress? Thanks!

[jsuarezruiz]

Oops, sorry for taking time to respond. What I was doing is available at: https://github.com/XamarinFormsCommunity/Xamarin.Forms/tree/feature/1708-pinssource
I will review it and continue.

[samhouts]

@jsuarezruiz Monthly ping! How is it going? Thanks!