如何在Xamarin iOS中更改UITableView中的行顺序

我有名为“myplaces”的List，名称，图像，坐标和距离。我用viewdidload方法中的表视图绑定了我的列表。我也使用Pull刷新控件来更新我的表格视图，但我只能更新单元格，例如图像，名称等。我想通过Distance属性更改行顺序，以便在表格视图中首先获取最近的位置。我正在更新我的列表顺序，如下所示。请帮帮我。如何在Xamarin iOS中更改UITableView中的行顺序

myPlaces = myPlaces.OrderBy(x => x.Distance).ToList();

这里是代码

UITableView table; 
    RrefreshTableSource tableSource; 
    bool useRefreshControl = false; 
    UIRefreshControl RefreshControl; 
    double PlaceRadius = 100; 
    public Places selectedplace; 
    AppDelegate appDelegate = UIApplication.SharedApplication.Delegate as AppDelegate; 
    public static LocationManager Manager { get; set; } 

    public PlacesViewController(IntPtr handle) : base (handle) 
    { 
     if (appDelegate.myPlaces.Count == 0) 
     { 
      Places p = new Places(); 
      appDelegate.myPlaces = p.LoadPlaces(); 
     } 

     Manager = new LocationManager(); 
     Manager.StartLocationUpdates(); 
    } 
    public override async void ViewDidLoad() 
    { 
     base.ViewDidLoad(); 
     UIApplication.Notifications.ObserveDidBecomeActive((sender, args) => 
     { 
      Manager.LocationUpdated += HandleLocationChanged; 
     }); 
     UIApplication.Notifications.ObserveDidEnterBackground((sender, args) => 
     { 
      Manager.LocationUpdated -= HandleLocationChanged; 
     }); 

     Title = "Places"; 
     table = new UITableView(new CGRect(0, 20, View.Bounds.Width, View.Bounds.Height - 20)); 
     tableSource = new RrefreshTableSource(appDelegate.myPlaces,this); 
     table.Source = tableSource; 
     table.RowHeight = 80; 
     await RefreshAsync(); 

     AddRefreshControl(); 
     Add(table); 
     table.Add(RefreshControl); 

    } 
    public override void PrepareForSegue(UIStoryboardSegue segue, NSObject sender) 
    { 
     //var indexPath = table.IndexPathForSelectedRow; 
     var indexPath = (NSIndexPath)sender; // this was the selected row 
     if (segue.Identifier == "detailsview") 
     { 
      var placedetail = segue.DestinationViewController as PlacesDetailViewController; 
      placedetail.selectedplace = appDelegate.myPlaces[indexPath.Row]; 
     } 
    } 
    public void HandleLocationChanged(object sender, LocationUpdatedEventArgs e) 
    { 
     // Handle foreground updates 
     CLLocation location = e.Location; 
     Manager.currentLocation = location; 
     //if (Manager.point != null) 
     //{ 
     // double curdistance = location.DistanceFrom(Manager.point); 
     // lblfarfrom.Text = "Far from " + Math.Round((curdistance), 2).ToString() + " meters"; 

     //} 
     CalcNearLocation(Manager.currentLocation); 
     //Manager.pointregionname = tbMessage.Text; 
     //Console.WriteLine("foreground updated"); 
    } 
    public override void ViewWillAppear(bool animated) 
    { 
     base.ViewWillAppear(animated); 
    } 
    public override void ViewDidAppear(bool animated) 
    { 
     base.ViewDidAppear(animated); 
    } 
    async Task RefreshAsync() 
    { 
     if (useRefreshControl) 
      RefreshControl.BeginRefreshing(); 

     if (useRefreshControl) 
      RefreshControl.EndRefreshing(); 

     table.ReloadData(); 
    } 
    #region * iOS Specific Code 
    void AddRefreshControl() 
    { 
     if (UIDevice.CurrentDevice.CheckSystemVersion(6, 0)) 
     { 

      RefreshControl = new UIRefreshControl(); 
      RefreshControl.ValueChanged += async (sender, e) => 
      { 
       CalcNearLocation(Manager.currentLocation); 
       await RefreshAsync(); 
      }; 

      useRefreshControl = true; 
     } 
    } 

    public void CalcNearLocation(CLLocation currentLocation) 
    { 
     if (appDelegate.myPlaces != null && appDelegate.myPlaces.Count > 0) 
     { 
      CLLocation closestLocation = null; 
      double smallestDistance = double.MaxValue; 
      string placename = string.Empty; 
      foreach (Places place in appDelegate.myPlaces) 
      { 
       CLLocation location = new CLLocation(place.points.Latitude, place.points.Longitude); 
       double distance = currentLocation.DistanceFrom(location); 
       place.Distance = ConvertMetersToKiloMeters(distance); 

       if (distance < smallestDistance) 
       { 
        smallestDistance = distance; 
        closestLocation = location; 
        placename = place.Name; 
       } 
      } 
      Console.WriteLine("Closest Location " + placename); 
      Manager.pointregion = new CLCircularRegion(closestLocation.Coordinate, PlaceRadius, placename); 
      Manager.pointregionname = placename; 
      appDelegate.myPlaces = appDelegate.myPlaces.OrderBy(x => x.Distance).ToList(); 

     } 
    }

来源

2017-04-22 vivek parikh

你在排序后调用ReloadData方法吗？你能展示更多的代码吗？ – iamIcarus

@iamIcarus用代码更新了问题。 –

您在appDelegate.myPlaces更新全局变量的项目，但你没有更新属于TableView中的源里面的物品。

你需要做这样的事情在你的RefreshAsync方法

async Task RefreshAsync() 
    { 
     if (useRefreshControl) 
      RefreshControl.BeginRefreshing(); 

     if (useRefreshControl) 
      RefreshControl.EndRefreshing(); 

     // Update the items inside the source , then reload data 
     ((RrefreshTableSource)table.Source).Items = appDelegate.myPlaces; 
     table.ReloadData(); 
    }

如果Items（或者是在源项目变量的名字）是不公开的，你需要将其暴露在

来源

2017-04-26 07:33:54 iamIcarus

如何在Xamarin iOS中更改UITableView中的行顺序

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