我使用TimePicker并显示默认值“12:00 AM”,我想将该字段设置为空白。
<TimePicker x:Name="timepicker" />
你必须创建自己的TimePicker
类,允许在XAML上使用NullableTime
。
该课程应如下:
public class MyTimePicker : TimePicker
{
private string _format = null;
public static readonly BindableProperty NullableDateProperty =
BindableProperty.Create<MyTimePicker, TimeSpan?>(p => p.NullableTime, null);
public TimeSpan? NullableTime
{
get { return (TimeSpan?)GetValue(NullableDateProperty); }
set { SetValue(NullableDateProperty, value); UpdateTime(); }
}
private void UpdateTime()
{
if (NullableTime.HasValue) { if (null != _format) Format = _format; Time = NullableTime.Value; }
else { _format = Format; Format = "pick ..."; }
}
protected override void OnBindingContextChanged()
{
base.OnBindingContextChanged();
UpdateTime();
}
protected override void OnPropertyChanged(string propertyName = null)
{
base.OnPropertyChanged(propertyName);
if (propertyName == "Time") NullableTime = Time;
}
}
然后在XAML上你应该创建你的控件并使用它如下:
<local:MyTimePicker NullableTime="{x:Null}" />
如果您使用此示例,您将看到应该选择默认值...