xamarin.forms - 如何获取 BindableProperty 的值？

Question

我想获得 BindableProperty 的值，因为我希望我的 BindableProperty 有两种状态，因为我可以区分

<local:MyEntry event="{Binding Flag,  Mode=TwoWay}">

在我的自定义条目中：

    public static  BindableProperty EventProperty =
                BindableProperty.Create("event", typeof(string), typeof(MyEntry), "sigle", propertyChanged: (obj, oldValue, newValue) =>
                { });
private string flag;
        public  string Flag
        {
            get { return flag; }
            set
            {
                if (flag != value)
                {
                    flag = value;
                    NotifyPropertyChanged("event");
                }
            }
        }

在我的 viewModel 中，这是代码：

private string flag;
        public string Flag
        {
            get { return flag; }
            set
            {
                if (flag != value)
                {
                    flag = value;
                    RaisePropertyChanged(() => Flag);
                }
            }
        }
private async Task Execute()
        {
            Flag = "Change";
        }

在我的自定义渲染器中

protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            base.OnElementPropertyChanged(sender, e);
                Console.WriteLine("HERE "+ (entry as MyEntry).Flag); 
//here i want to get the value

在答案的帮助下

if (e.PropertyName == MyEntry.EventProperty.PropertyName)
            {
                var entry = Element as MyEntry;
                var Flag = entry.Flag;
                Console.WriteLine("... "+ Flag);

标签： xamarin.forms

Answer 1

在自定义渲染器中

 public static BindableProperty FlagProperty = BindableProperty.Create("Flag", typeof(string), typeof(MyEntry), string.Empty, propertyChanged: (obj, oldValue, newValue) =>
        {
            var entry = obj as MyEntry;
            entry.Flag = newValue.ToString();
        });
private string flag;
public  string Flag
{
   get { return flag; }
   set
   {
      if (flag != value)
      {
         flag = value;
         NotifyPropertyChanged("Flag");
      }
   }
}

在自定义渲染器中

protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
   base.OnElementPropertyChanged(sender, e);

   if (e.PropertyName == MyEntry.EventProperty.PropertyName)
   {
       //  will been invoked when the value changed
       var entry = Element as MyEntry;
       var Flag = entry.Flag;
   }


}