xamarin.ios - UIPickerViewModel GetView 为 UIPickerView monotouch 调用了无限次

Question

我有一个 UIPickerView，它使用自定义 UIPickerViewModel 来覆盖 UIPicker 视图中显示的视图。

当我第一次打开 UIPickerView 时，一切顺利，我可以选择一个项目而不能选择什么。

如果所选项目是 UIPicker 中的第一个或第二个项目，我不会遇到任何问题。但是，如果我选择说第三个项目，关闭 Picker 然后尝试再次选择另一个选项，UIPickerView 永远不会显示在屏幕上。

我发现我的 PickerViewModel 上的 GetView 方法被一遍又一遍地调用，用于选定的行以及之后的行。我做过什么可能导致这种行为的事情吗？下面是我的 PickerViewModel

public class AddressPickerViewModel : UIPickerViewModel
{
    private ShippingView view;
    public AddressPickerViewModel(ShippingView view)
    {
        this.view = view;
    }

    private AddressPickerCell currentSelectedCell;
    public override UIView GetView(UIPickerView picker, int row, int component, UIView view)
    {
        if (view == null)
        {
            view = new AddressPickerCell();
            var views = NSBundle.MainBundle.LoadNib(AddressPickerCell.Key, view, null);
            view = Runtime.GetNSObject(views.ValueAt(0)) as AddressPickerCell;
        }

        var pickerCell = (AddressPickerCell)view;
        pickerCell.Selected = false;
        pickerCell.ShippingAddress = this.view.ViewModel.Addresses.ToArray()[row].Address;
        return view;

    }
    public override int GetComponentCount(UIPickerView v)
    {
        return 1;
    }
    public override int GetRowsInComponent(UIPickerView pickerView, int component)
    {
        return this.view.ViewModel.Addresses.Count;
    }
    public override void Selected(UIPickerView picker, int row, int component)
    {
        if (this.currentSelectedCell != null) 
        {
            this.currentSelectedCell.Selected = false;
        }
        view.ViewModel.SelectedAddress=
            this.view.ViewModel.Addresses.ElementAt(picker.SelectedRowInComponent(0));

        var cell = picker.ViewFor(row, component) as AddressPickerCell;
        if (cell != null)
        {
            this.currentSelectedCell = cell;
            this.currentSelectedCell.Selected = true;
        }


    }
    public override float GetComponentWidth(UIPickerView picker, int component)
    {
        if (component == 0)
            return 300f;
        else
            return 40f;
    }

    public override float GetRowHeight(UIPickerView picker, int component)
    {
        return 140f;
    }
}