为什么选择器在 xamarin 形式中两次触发 onselectedindexchangedevent

Question

Why picker twice time triggered first time i get the values of Selecteditem second time it seems to be null all. How to resolve this issue.

private void OnSelectedIndexChanged(object sender, EventArgs e)
        {
            double vatPercent;
            object selectedPicker = ((Picker)sender).BindingContext;

            Picker picker = ((Picker)sender);
            object vatItem = picker.SelectedItem;

            int index = picker.SelectedIndex;
            if (vatItem != null)
            {
                VatRate vatRate = vatItem as VatRate;
                vatPercent = vatRate.Rate;
            }
            else
                vatPercent = 0;
}

Answer 1

This issue has been reported:

https://github.com/xamarin/Xamarin.Forms/issues/2075 https://github.com/xamarin/Xamarin.Forms/issues/7646

You could try the suggestions below:

1. Update Xamarin Forms to latest version.
2. Use the ObservableCollection as ItemSource.