我有下一个转换器代码，类似于Xamarin.Forms Binding Converter后的示例，但当值进入方法时，只有属性Path=“DeviceHasScanner”，而绑定属性从未被调用：（

public class BoolToObjectConverter<T> : IValueConverter
    {
       public T TrueObject { set; get; }

       public T FalseObject { set; get; }

       public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
       {
           return (bool)value ? TrueObject : FalseObject;
       }

       public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
       {
           return ((T)value).Equals(TrueObject);
       }
   }

我试着用这样的方式来实现它：

<Image HorizontalOptions="Center" WidthRequest="200">
     <Image.Source>
         <Binding Source="{Binding DeviceHasScanner}">
               <Binding.Converter>
                     <converters:BoolToObjectConverter x:TypeArguments="x:String"  TrueObject="presstoscan.png" FalseObject="scanwithcamera.png" />
                </Binding.Converter>
          </Binding>
     </Image.Source>
 </Image>

而viewmodel中的布尔绑定属性是：

public bool DeviceHasScanner
    {
        get 
        {
            return Settings.Get.DeviceHasScanner; //This code return true or false
        }
    }

实施它的正确方法是什么？