c# - 无法使用必应 map 通过 mvvm 将 map 地理坐标中心绑定(bind)到 Windows Phone 上的 map

Question

我正在尝试根据给定实例在 map 上显示的各种路线动态设置 map 控件的中心属性。我在这里使用路线的起点作为地理坐标中心。为此，我尝试使用 bing map 通过 Windows Phone 应用程序上的 mvvm 将地理坐标中心绑定(bind)到 map 控件。我能够通过纬度和经度获取中心位置的数据，但无法将其绑定(bind)到 UI(xaml) 页面。

下面是我的RouteViewModel类

 private Location startPoint;
    public Location StartPoint
    {
        get { return startPoint; }
        set
        {
            startPoint = value;
            Change("StartPoint");
        }
    }

   private System.Device.Location.GeoCoordinate centre;

    public System.Device.Location.GeoCoordinate Centre
    {
        get { return centre; }
        set { centre = value; }
    }

    private string getcenter;

    public string Getcenter
    {
        get { return getcenter; }
        set { getcenter = value; }
    }

    private Location endPoint;
    public Location EndPoint
    {
        get { return endPoint; }
        set
        {
            endPoint = value;
            Change("EndPoint");
        }
    }

    private ObservableCollection<Location> routePoints;
    public ObservableCollection<Location> RoutePoints
    {
        get { return routePoints; }
        set
        {
            routePoints = value;
            Change("RoutePoints");
        }
    }

    private ObservableCollection<ItineraryItem> itinerary;
    public ObservableCollection<ItineraryItem> Itinerary
    {
        get
        {
            return itinerary;
        }
        set
        {
            itinerary = value;
            Change("Itinerary");
        }
    }


   private void LocationLoaded()
    {
        if (fromLocation != null && toLocation != null)
        {
            var fromWaypoint = new Waypoint();
            fromWaypoint.Description = "From";
            fromWaypoint.Location = new Location();
            fromWaypoint.Location.Altitude = fromLocation.Altitude;
            fromWaypoint.Location.Latitude = fromLocation.Latitude;
            fromWaypoint.Location.Longitude = fromLocation.Longitude;

            var toWaypoint = new Waypoint();
            toWaypoint.Description = "To";
            toWaypoint.Location = new Location();
            toWaypoint.Location.Altitude = toLocation.Altitude;
            toWaypoint.Location.Latitude = toLocation.Latitude;
            toWaypoint.Location.Longitude = toLocation.Longitude;

            var routeRequest = new RouteRequest();
            routeRequest.Credentials = new Credentials();
            routeRequest.Credentials.ApplicationId = App.BingApiKey;
            routeRequest.Waypoints = new System.Collections.ObjectModel.ObservableCollection<Waypoint>();
            routeRequest.Waypoints.Add(fromWaypoint);
            routeRequest.Waypoints.Add(toWaypoint);
            routeRequest.Options = new RouteOptions();
            routeRequest.Options.RoutePathType = RoutePathType.Points;
            routeRequest.UserProfile = new Utils.WP7.Bing.BingRoute.UserProfile();
            routeRequest.UserProfile.DistanceUnit = Utils.WP7.Bing.BingRoute.DistanceUnit.Kilometer;

            var routeClient = new RouteServiceClient("BasicHttpBinding_IRouteService");
            routeClient.CalculateRouteCompleted += new EventHandler<CalculateRouteCompletedEventArgs>(OnRouteComplete);
            routeClient.CalculateRouteAsync(routeRequest);
        }
    }


   private void OnRouteComplete(object sender, CalculateRouteCompletedEventArgs e)
    {
        if (e.Result != null && e.Result.Result != null && e.Result.Result.Legs != null & e.Result.Result.Legs.Any())
        {
            var result = e.Result.Result;
            var legs = result.Legs.FirstOrDefault();

            StartPoint = legs.ActualStart;
            EndPoint = legs.ActualEnd;
            RoutePoints = result.RoutePath.Points;
            Itinerary = legs.Itinerary;

     //Centre = StartPoint;
             Getcenter = string.Format("{0},{1}", StartPoint.Latitude.ToString(), StartPoint.Longitude.ToString());

            RaiseRouteResolved();
        }
     }

以下是我的.xaml.cs页面中的代码，后面是我的xaml页面中的代码。

 (DataContext as RouteViewModel).ResolveRouteFromCurrent();



<maps:Map x:Name="RMaps" Center="{Binding Getcenter}" ZoomLevel="5" CredentialsProvider="{StaticResource MapCredentials}">

我也尝试绑定(bind) GeoCoordinate 类型的“Centre”(在上面的代码中注释)，但这并没有解决我的问题。有人可以告诉我解决此问题的方法吗...在此先感谢。

Answer 1

您的类需要实现 INotifyPropertyChanged 并且您的 Getcenter 属性需要在值发生变化时引发 PropertyChangedEvent 以便数据绑定(bind)在值发生时起作用更新。