如何在Xamarin.Forms中的UIView内部UITextField时引发事件？

Question

我在UITextfield内部试图为UIView举起活动。

UIView view = new UIView();
UITextField textfield = new UITextField();
textField.TouchDown += textfield_TouchDown;
view.AddSubView(textfield);

// event not raised.
void textfield_TouchDown(object s, EventArgs args)
{
    // your code here
}

我试图添加手势，但它无效。

请参阅以下代码

UITextField textfield = new UITextField();
UITapGestureRecognizer gestureRecognizer = new UITapGestureRecognizer();
gestureRecognizer.NumberOfTapsRequired = 1; 
if (textfield != null)
{
    textfield.UserInteractionEnabled = true;
    gestureRecognizer.AddTarget(() =>
    {
         // click event for lable/image
         OnTapped(gestureRecognizer);
    });
    textfield.AddGestureRecognizer(gestureRecognizer);
}

private void OnTapped(UITapGestureRecognizer gestureRecognizer)
{
    //your code here
}

请就此建议您的想法？

此致

斯里尼瓦桑