Xamarin Forms CustomPin iOS Render

无法在视图中显示以下列表中的所有插针. 注:我下面的样本不是xamarin forms documentation个中的一部分.这是我的 idea ，也许我可以将这两个列表结合在一起，并在 map 上显示.

1. Pin.id==1(主针)常量更改其位置，try 添加不同的图像或 colored颜色
2. 在加载 map 时，我正在try 显示另外9个别针(静态别针)，这些别针不会移动.我再一次指定了不同的图像 colored颜色 . 结果，一个列表将覆盖另一个列表.因此，我要么显示引脚1，要么显示其他9个引脚.但我不能同时把10个插针放在屏幕上.

下面是如何创建第一个静态列表和单个PIN

  public class CustomMap : Map
        {
            public List<CustomPin> AdditionalPins { get; set; }
            public List<CustomPin> CustomPins { get; set; }
           
       
    public CustomMap()
    {
       
        CustomPins = new List<CustomPin>();
        
        AdditionalPins = new List<CustomPin>();
    }

在主页上:两个PIN列表

var customPin = new CustomPin
                                {
                                    PinId = 1,
                                    // Position = new Position(37.7749, -122.4194), // Set the position of the pin
                                    Label = "Custom Pin",
                                    Address = "Custom Address",
                                    Rotation = -45 // Set the rotation angle in degrees
                                };
                                Xamarin.Forms.Device.BeginInvokeOnMainThread(() =>
                                {
                                    customPin.Position = pos;
                                    // pins.Position = pos;
        
                                    if (myMap.Pins.Count == 0)
                                    {
                                        
                                        myMap.Pins.Add(customPin);
                                    
                                    }....

2.一组静态引脚

     foreach (var coordinate in coordinates)
                    {
                        var poss = new Position(coordinate.Latitude, coordinate.Longitude);
                        CustomPin additionalPin = new CustomPin
                        {
                            PinId = 20,
                            Label = "Additional Pin",
                            Name = coordinate.StopNumber
                            // Add more properties as needed
                        };
    
                        myMap.AdditionalPins.Add(additionalPin);

现在，我得到了两个列表，一个有一个针脚，每10秒更新一次位置，另一个(adittionalpins=9组坐标) 在这里，将这两个列表结合起来

   private List<CustomPin> GetAllPins(MKPointAnnotation mKPointAnnotation)
        {
            List<CustomPin> matchingPins = new List<CustomPin>();

            if (mKPointAnnotation != null)
            {
                var position = new Position(mKPointAnnotation.Coordinate.Latitude, mKPointAnnotation.Coordinate.Longitude);


                // Check Pins collection
                foreach (var pin in ((CustomMap)Element).Pins)
                {
                   
                        matchingPins.Add(pin as CustomPin);
                        // If a match is found in Pins, no need to check AdditionalPins, break out of the loop
                       
                    
                }

              //  Check AdditionalPins collection only if a match is not found in Pins


                    foreach (var additionalPin in ((CustomMap)Element).AdditionalPins)
                {

                    matchingPins.Add(additionalPin);
                    // If a match is found in AdditionalPins, no need to continue the loop



                }

            }

            return matchingPins;
        }

protected override MKAnnotationView GetViewForAnnotation(MKMapView mapView, IMKAnnotation annotation)
        {
            if (annotation is MKUserLocation)
                return null;
         

            var result = GetAllPins(annotation as MKPointAnnotation); //HERE -- get all the items 
            if (result != null)
            {
                
                List<CustomPin> pins = result;

                if (pins != null && pins.Any())
                {
                    
                    foreach (var D in pins)
                    {
                          if (annotationView == null)
                         {
                         annotationView = new MKAnnotationView(annotation, reuseIdentifier);

                            if (D.PinId == 1) //it gets here the first time 
                            {
                                annotationView.Image = UIImage.FromFile("lilocation.png");
                              
                            }
                            else if (D.PinId == 20) //never assign this part to the view 
                            {
                                annotationView.Image = UIImage.FromFile("red.png");
                            }

                           
                        }
                       
                    }
                }

                    return annotationView;
                
            }

目标是显示列表中的每一项及其图像和行为.问题是，视图只在第一次得到NULL.