我正試圖將兩個標籤與點擊StackLayout上的日期進行綁定。 stacklayout有三個元素,一個是顯示日期的標籤,另一個是顯示月份和年份的標籤,第三個元素是可見性設置爲false的日期選擇器。Xamarin使用Prism將行爲應用於StackLayout表格
我的XAML
<StackLayout>
<Label Text="End Date" Style="{StaticResource H2Style}" HorizontalOptions="Center"/>
<Label Text="26" HorizontalOptions="Center"/>
<Label Text="Mar 2017" HorizontalOptions="Center"/>
<DatePicker x:Name="endDatePicker" IsVisible="false" />
<StackLayout.Behaviors>
<b:EventToCommandBehavior EventName="DateTapped"
Command="{Binding DatePickerCommand}"
CommandParameter= "{x:Reference endDatePicker}" />
</StackLayout.Behaviors>
</StackLayout>
我想顯示在stackLayout的點擊日期選擇器對話框。
我的視圖模型
public class MyViewModel : BindableBase
{
public DelegateCommand<Object> DatePickerCommand { get; set; }
public MyViewModel()
{
DatePickerCommand = new DelegateCommand<Object>(DateTapped);
}
private void DateTapped(Object obj)
{
Device.BeginInvokeOnMainThread(() =>
{
if (endDatePicker.IsFocused)
endDatePicker.Unfocus();
endDatePicker.Focus();
});
}
}
,但我得到了以下錯誤:
Objective-C exception thrown. Name: NSInternalInconsistencyException
Reason: Application windows are expected to have a root view
controller at the end of application launch
Native stack trace:
0 CoreFoundation 0x0000000104b7bb0b __exceptionPreprocess + 171
1 libobjc.A.dylib 0x000000010f757141 objc_exception_throw + 48
2 CoreFoundation 0x0000000104b7fcf2 +[NSException raise:format:arguments:] + 98
3 Foundation 0x0000000105732536 -[NSAssertionHandler handleFailureInMethod:object:file:lineNumber:description:] + 193
4 UIKit 0x0000000109adac46 -[UIApplication _runWithMainScene:transitionContext:completion:] + 3343
5 UIKit 0x0000000109ad77f3 -[UIApplication workspaceDidEndTransaction:] + 182
6 FrontBoardServices 0x000000011246f5f6 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 24
7 FrontBoardServices 0x000000011246f46d -[FBSSerialQueue _performNext] + 186
8 FrontBoardServices 0x000000011246f7f6 -[FBSSerialQueue _performNextFromRunLoopSource] + 45
9 CoreFoundation 0x0000000104b21c01 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
10 CoreFoundation 0x0000000104b070cf __CFRunLoopDoSources0 + 527
11 CoreFoundation 0x0000000104b065ff __CFRunLoopRun + 911
12 CoreFoundation 0x0000000104b06016 CFRunLoopRunSpecific + 406
13 UIKit 0x0000000109ad608f -[UIApplication _run] + 468
14 UIKit 0x0000000109adc134 UIApplicationMain + 159
15 ??? 0x00000001282fcd94 0x0 + 4969188756
16 ??? 0x00000001282fc9dd 0x0 + 4969187805
,我將不勝感激,如果有人可以幫助我這個
你可能想以趕上真正的例外 - https://stackoverflow.com/q/43556274/1155650 –