我在ObservableCollection中有一个选取器，我需要用自定义命令绑定SelectedIndexChanged属性，因为它将对包含此选取器的对象的同一示例进行一些更改，而在此之外没有。我知道BindingContext设置正确，因为ItemsSource按预期加载。但VS不编译并显示以下消息：
Binding SelectedIndexChanged: No property, BindableProperty, or event found for "SelectedIndexChanged", or mismatching type between value and property.
下面是我的代码：

public event EventHandler HourChangedIndex
{
    add
    {
       HourChangedIndex += new EventHandler((sender, e) =>
       {
           Hours.Add(((Picker)sender).SelectedItem as string);
           Hours = new ObservableCollection<string>(Hours.OrderBy(i => i));
        });
     }
     remove
     {
        HourChangedIndex -= new EventHandler((sender, e) =>
        {
            Hours.Add(((Picker)sender).SelectedItem as string);
            Hours = new ObservableCollection<string>(Hours.OrderBy(i => i));
        });
      }
}

我做错了什么或错过了什么？