MvxSpinner项应为空，直到不从下拉列表中选择

Question

我正在使用MvxSpinner并且只想在spinner上显示下拉选定值。目前它显示下拉列表中的第一项但我想显示空白，因为我没有从下拉列表中选择任何值。

微调

<MvvmCross.Binding.Droid.Views.MvxSpinner
        android:id="@+id/mySpinner"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        local:MvxDropDownItemTemplate="@layout/myspinner_item"
        local:MvxItemTemplate="@layout/myspinner_item"
        android:layout_marginLeft="0dp"
        android:dropDownWidth="257dp"
        android:dropDownSelector="@drawable/list_item_selector"
        android:layout_centerInParent="true"
        android:spinnerMode="dropdown"
        local:MvxBind="ItemsSource MyItems; HandleItemSelected SelectCommand" />

myspinner_item

<?xml version="1.0" encoding="utf-8"?>
<MvvmCross.Binding.Droid.Views.MvxLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:local="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/list_item_selector"
    android:orientation="horizontal">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="32dp"
        android:textSize="15sp"
        android:textColor="#de000000"
        android:lineSpacingExtra="5sp"
        android:singleLine="true"
        android:text=""
        android:layout_marginTop="6dp"
        android:layout_marginBottom="6dp"
        android:layout_marginLeft="24dp"
        local:MvxBind="Text Description; Typeface StringToFont('Effra_Rg')" />
</MvvmCross.Binding.Droid.Views.MvxLinearLayout>