UIDatePicker停止工作IOS14

Question

由于我在我的mac上更新了Xcode 12和VS (2019 8.7.8 build 4)，并将Xamarin更新为最新版本(Xamarin.iOS 14.0.0.0)，我发现我无法使用UIDatePicker。

DatePicker

查看文档，https://developer.apple.com/documentation/uikit/uidatepicker需要设置样式，可能需要设置preferredDatePickerStyle，但这些属性都不是我可以在(Xamarin)代码中设置的。

有没有人找到了一种方法，可以通过这个方法来选择日期？

Answer 1

一旦我们设置了preferredDatePickerStyle和sizeToFit，它就能工作了，下面给出了示例代码。

_datePicker = new UIDatePicker(new CGRect(0, 30, 0, 0));
_datePicker.AutoresizingMask = UIViewAutoresizing.FlexibleRightMargin;
_datePicker.Frame = new CGRect(_datePicker.Frame.Location, new CGSize(300, _datePicker.Frame.Size.Height));
_datePicker.Mode = _datePickerMode;
_datePicker.Date = (NSDate)_defaultDate;
_datePicker.PreferredDatePickerStyle = UIDatePickerStyle.Wheels; //Add this in ios14
_datePicker.SizeToFit(); //Add this in ios14

Answer 2

我已经解决了这个问题：

_datePicker.SetValueForKey(new NSNumber(1), new NSString("preferredDatePickerStyle"));

它现在正在显示正确的选择器。

日期选择器

Answer 3

我基本上将其他答案的所有细节集中到iOS中的Xamarin表单的相应实现中(省略了iOS中CreateNativeControl、OnElementPropertyChanged和自定义方法的实现)：

protected override void OnElementChanged(ElementChangedEventArgs<DatePicker> e)
{
    const int iosVersionMajorForDatePickerStyleFeature = 13;
    const int iosVersionMinorForDatePickerStyleFeature = 4;
    base.OnElementChanged(e);

    if (e.OldElement != null || Element == null)
    {
        return;
    }

    //Switch back to the Wheels style for the datePicker (in iOS 14 the default of Automatic uses the Compact style)
    if (UIDevice.CurrentDevice.CheckSystemVersion(iosVersionMajorForDatePickerStyleFeature, iosVersionMinorForDatePickerStyleFeature)
        && Control?.InputView is UIDatePicker datePicker && datePicker.PreferredDatePickerStyle != UIDatePickerStyle.Wheels)
    {
        datePicker.PreferredDatePickerStyle = UIDatePickerStyle.Wheels;
        datePicker.SizeToFit();
    }

    //Do whatever other customization is desired
    //UpdateBorderColor();
    //UpdateBorderWidth();
    //UpdateCornerRadius();
    //UpdatePadding();
}