具有MVVMCross中的自定义控件的绑定转换器

Question

我创建了自己的自定义视图。此多列表选择器从列表中选择多行。 当他尝试绑定数据时，会出现此错误。 “ SetValue失败，发生异常-ArgumentException：类型为'System.Collections.Generic.List 1[System.Object]' cannot be converted to type 'System.Collections.Generic.List 1 [isvk.Core.Models.NtdChecked]'的对象”“

我的控制权

<isvk.Controls.MultipleListPicker
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_marginTop="@dimen/report_field_margin_top_bottom"
                        local:lp_label="@string/ReportMTRDataNtd"
                        local:lp_icon="@drawable/icon_list"
                        local:lp_targetProperty="Title"
                        local:MvxBind="Items Ntds; CheckedItems NtdCheckedList, Converter=ListObject; NewItem AddNewNtdItemCommand" />

我的转换器：

public class ListObjectConverter : MvxValueConverter
    {
        public override object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return value;
        }
}

我创建了自己的Converter，但无法连接。在调试模式下，程序不会进入转换器。在下面的代码中可以更改的位置或内容。

我的MultipleListPicker：

 public class MultipleListPicker : ListPicker 
{
    private readonly IList<object> _checkedItemsCancelable = new List<object>();
    private IEnumerable<object> _checkedItems;

    public MultipleListPicker(Context context, IAttributeSet attrs)
        : base(context, attrs)
    {
        _listView.ChoiceMode = ChoiceMode.Multiple;
        _dialog = new AlertDialog.Builder(Context).SetView(_pickerListView).SetCancelable(true)
            .SetPositiveButton(Resource.String.ReadyText, OnReadyClicked)
            .SetNegativeButton(Resource.String.CancelText, (sender, args) => _dialog.Dismiss()).Create();
    }

    public IEnumerable CheckedItems
    {
        get { return _checkedItems; }
        private set
        {
            _checkedItems = new List<object>((IEnumerable<object>) value);
            SelectionChanged?.Invoke(this, new MultipleSelectionEventArgs(_checkedItems));
        }
    }

    protected override void OnClick(object sender, EventArgs args)
    {
        _listView.ClearChoices();
        _checkedItemsCancelable.Clear();

        for (var i = 0; i < _listView.ChildCount; i++)
        {
            SetDeselectedBackground(i);
        }

        if (CheckedItems != null)
        {
            foreach (var obj in CheckedItems)
            {
                SelectItem(obj);
            }
        }

        base.OnClick(sender, args);
    }

    protected override void ListViewOnItemSelected(object obj)
    {
        if (!IsItemSelected(obj))
        {
            SelectItem(obj);
        }
        else
        {
            DeselectItem(obj);
        }
    }

    private void SetSelectedBackground(int index)
    {
        try
        {
            var v = _listView.GetChildAt(index);
            v.SetBackgroundResource(Resource.Color.colorPrimary);
        }
        catch (Exception ex)
        {
            Trace.WriteLine(ex.Message);
        }

    }

    private void SelectItem(object obj)
    {
        var index = _listView.Adapter.GetPosition(obj);
        _listView.SetItemChecked(index, true);

        _checkedItemsCancelable.Add(obj);

        SetSelectedBackground(index);
    }

    private void SetDeselectedBackground(int index)
    {
        var v = _listView.GetChildAt(index);
        v.SetBackgroundResource(Resource.Color.white);
    }

    private void DeselectItem(object obj)
    {
        var index = _listView.Adapter.GetPosition(obj);
        _listView.SetItemChecked(index, false);

        _checkedItemsCancelable.Remove(obj);

        SetDeselectedBackground(index);
    }

    private bool IsItemSelected(object obj)
    {
        return _checkedItemsCancelable.Contains(obj);
    }

    private void OnReadyClicked(object sender, DialogClickEventArgs eventArgs)
    {
        var hasSelection = false;
        var builder = new StringBuilder(string.Empty);

        foreach (var checkedItem in _checkedItemsCancelable)
        {
            hasSelection = true;
            builder.Append(checkedItem);
            builder.Append("; ");
        }

        if (hasSelection)
        {
            _contentTextView.Text = builder.ToString();
        }
        else
        {
            _contentTextView.SetText(Resource.String.NotSelectedText);
        }

        CheckedItems = _checkedItemsCancelable;
    }

    public event EventHandler<MultipleSelectionEventArgs> SelectionChanged;
}

public class MultipleSelectionEventArgs : EventArgs
{
    public MultipleSelectionEventArgs(IEnumerable checkedItems)
    {
        CheckedItems = checkedItems;
    }

    public IEnumerable CheckedItems { get; }
}

我的项目结构： enter image description here