MvxBind：无法为绑定创建目标绑定？

Question

我在radio buttons内显示listview并绑定了onClick，但我收到了绑定失败错误。 下面是我的ListView：

<Mvx.MvxListView
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:id="@+id/listview"
                local:MvxBind="ItemsSource QuestionList; ItemClick ChoiceCheckedClick"
                local:MvxItemTemplate="@layout/item_questions"
                android:clickable="true"
                android:layout_margin="10dp"
                android:layout_marginBottom="20dp" />

项目模板：

 <RadioButton
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:id="@+id/radioButton1"
                    android:textColor="#000000"
                    android:clickable="true"
                    local:MvxBind="Text OptionA; onClick choiceClicked" />
                <RadioButton
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#000000"
                    local:MvxBind="Text OptionB"
                    android:id="@+id/radioButton2" />
                <RadioButton
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#000000"
                    local:MvxBind="Text OptionC"
                    android:id="@+id/radioButton3" />
                <RadioButton
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textColor="#000000"
                    local:MvxBind="Text OptionD"
                    android:id="@+id/radioButton4" />
            </RadioGroup>

我的视图模型：

  private IMvxCommand _choiceCheckedClick;
                public IMvxCommand ChoiceCheckedClick
                {
                    get
                    {
                        _choiceCheckedClick = _choiceCheckedClick ?? new MvxCommand<Question>(btnClick);
                        return _choiceCheckedClick;
                    }
                }

                public void btnClick(Question item)
                {
                    //Do something
                }

My Wrapper课程：

 namespace EducationAppPCL.Utility
    {
       public  class QuestionWrapper
        {
           Question _questionItem;
           QuestionsViewModel _questionViewModel;

           public QuestionWrapper(Question questionItem, QuestionsViewModel questionViewModel)
           {
               _questionItem = questionItem;
               _questionViewModel = questionViewModel;
           }

           public IMvxCommand choiceClicked
           {
               get
               {
                   return new MvxCommand(() => _questionViewModel.btnClick(_questionItem));
               }
           }

           public Question QuestionItem
           {
               get
               {
                   return _questionItem;
               }
           }


       }

以下是我的模特：

public class Question
{
    // [AutoIncrement,PrimaryKey]
    [PrimaryKey]
    public int Id { get; set; }

    public Nullable<int> AssignmentId { get; set; }
    public string QuestionText { get; set; }
    public string Description { get; set; }
    public string Options { get; set; }
    public Nullable<int> Score { get; set; }
    public string Type { get; set; }
    public string OptionA { get; set; }
    public string OptionB { get; set; }
    public string OptionC { get; set; }
    public string OptionD { get; set; }
    public bool RadioVisible { get; set; }
    public bool TexboxVisible { get; set; }
    public bool SubmitVisible { get; set; }
    public bool NextVisible { get; set; }

    public bool OptionASelected { get; set; }
    public bool OptionBSelected { get; set; }
    public bool OptionCSelected { get; set; }
    public bool OptionDSelected { get; set; }
    public string AnswerGiven { get; set; }

    public bool choiceClicked { get; set; }
    public string CreatedDate { get; set; }
    public string ModifiedDate { get; set; }

我收到了以下错误：

[0:] 
MvxBind:Warning: 15.50 Failed to create target binding for binding onClick for choiceClicked
[0:] MvxBind:Warning: 15.50 Failed to create target binding for binding onClick for choiceClicked
09-11 10:51:07.880 I/mono-stdout( 1929): MvxBind:Warning: 15.50 Failed to create target binding for binding onClick for choiceClicked
[0:] 
09-11 10:51:07.900 W/EGL_genymotion( 1929): eglSurfaceAttrib not implemented
MvxBind:Warning: 15.53 Failed to create target binding for binding onClick for choiceClicked
[0:] MvxBind:Warning: 15.53 Failed to create target binding for binding onClick for choiceClicked
09-11 10:51:07.908 I/mono-stdout( 1929): MvxBind:Warning: 15.53 Failed to create target binding for binding onClick for choiceClicked
[0:] 
MvxBind:Warning: 15.54 Failed to create target binding for binding onClick for choiceClicked
[0:] MvxBind:Warning: 15.54 Failed to create target binding for binding onClick for choiceClicked
09-11 10:51:07.920 I/mono-stdout( 1929): MvxBind:Warning: 15.54 Failed to create target binding for binding onClick for choiceClicked