我有一个应用程序,我列出了一些项目,然后更改为另一个页面进行编辑.在编辑页面中,我有一些字段,我需要从列表中选择一个值,我在另一个页面中加载.我从编辑页面调用列表页面,从编辑页面视图模型传递一个方法,以便在进行选择时调用,以便我可以更新我的模型和绑定.
问题是,有时候,当返回到编辑页面时,调试器会在生成的文件App.g.i.cs中打破
"Error HRESULT E_FAIL has been returned from a call to a COM component." exception.
我通过将其替换为虚拟页面并删除编辑页面设置的任何回调,从值列表的异步加载中排除了可能的错误.错误仍然发生.
编辑页面的导航缓存模式设置为必需,因此我不会丢失以前的更改.我尝试没有所需的缓存模式,仍然得到错误.
似乎解决这个问题的唯一一件事就是我从编辑页面xaml中删除了使用自定义转换器的绑定,但我在其他页面中有那些并且从未遇到过问题. (见更新)
#if DEBUG && !disABLE_XAML_GENERATED_BREAK_ON_UNHANDLED_EXCEPTION UnhandledException += (sender,e) => { if (global::System.Diagnostics.Debugger.IsAttached) global::System.Diagnostics.Debugger.Break(); };
这是编辑页面的xaml：
<Page.Resources>
<converters:BooleanToVisibilityConverter x:Key="BoolToVisibility" />
<converters:StringFormatConverter x:Key="StringFormat" />
<converters:DateTimetoDateTimeOffsetConverter x:Key="DateOffset" />
<converters:DateTimetoTimeSpanConverter x:Key="TimeSpan" />
</Page.Resources>
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid.ColumnDeFinitions>
<ColumnDeFinition Width="*" />
</Grid.ColumnDeFinitions>
<Grid.RowDeFinitions>
<RowDeFinition Height="auto" />
<RowDeFinition Height="auto" />
<RowDeFinition Height="*" />
</Grid.RowDeFinitions>
<fieldSelectControl:BackButtonAndTitle Title="Page Title" />
<StackPanel Grid.Row="1" Orientation="Horizontal">
<Button Name="HomeButton"
Width="70"
Height="50"
Background="Black"
Content=""
FontFamily="Segoe MDL2 Assets"
FontSize="30" />
<TextBlock Name="PageTitle"
FontSize="36"
Text="{Binding OrderTitle}" />
</StackPanel>
<ProgressRing Grid.Row="2" IsActive="{Binding IsLoading}" />
<ScrollViewer Grid.Row="2"
Height="Auto"
HorizontalScrollBarVisibility="disabled"
VerticalScrollBarVisibility="Auto"
Visibility="{Binding Path=FinishedLoading,Converter={StaticResource BoolToVisibility}}">
<StackPanel Margin="20,10,20,30">
<TextBlock Margin="0,5,5"
Style="{StaticResource DetailLabel}"
Text="Date" />
<DatePicker Date="{Binding Day,Mode=TwoWay,Converter={StaticResource DateOffset}}" />
<TextBlock Margin="0,15,5"
Style="{StaticResource DetailLabel}"
Text="Type" />
<ComboBox ItemsSource="{Binding Combovalues}" SelectedItem="{Binding SelectedHourType,Mode=TwoWay}" />
<TextBlock Margin="0,5"
Style="{StaticResource DetailLabel}"
Text="Start" />
<TimePicker ClockIdentifier="24HourClock" Time="{Binding StartTime,Converter={StaticResource TimeSpan}}" />
<TextBlock Margin="0,5"
Style="{StaticResource DetailLabel}"
Text="End" />
<TimePicker ClockIdentifier="24HourClock" Time="{Binding EndTime,5"
Style="{StaticResource DetailLabel}"
Text="Amount" />
<TextBox InputScope="Number" Text="{Binding HValue,Mode=TwoWay}" />
<fieldSelectControl:FieldWithIconSelector x:Name="fsSelect"
IconClickedEvent="btnClose_Click"
IconField=""
TitleField="Add..."
TitleIconField=""
ValueField="" />
<ScrollViewer Height="Auto"
HorizontalScrollBarVisibility="disabled"
VerticalScrollBarVisibility="Auto">
<ListView x:Name="lstOrders"
Height="auto"
MaxHeight="600"
HorizontalAlignment="Stretch"
IsItemClickEnabled="True"
ItemClick="lstOrders_ItemClick"
ItemsSource="{Binding SelectedEmployees,Mode=OneWay}">
<ListView.ItemTemplate>
<DataTemplate x:DataType="data:Responsible">
<fieldSelectControl:FieldWithIconSelector x:Name="fsEmployees"
IconClickedEvent="fsEmployees_IconClickedEvent"
IconField=""
TitleField=""
TitleIconField=""
ValueField="{Binding Name}" />
</DataTemplate>
</ListView.ItemTemplate>
<ListView.ItemContainerStyle>
<Style targettype="ListViewItem">
<Setter Property="HorizontalContentAlignment" Value="Stretch" />
</Style>
</ListView.ItemContainerStyle>
</ListView>
</ScrollViewer>
<Button Name="btnSave"
Margin="0,15"
HorizontalAlignment="Stretch"
Click="btnSave_Click"
Visibility="{Binding Path=FinishedSaving,Converter={StaticResource BoolToVisibility}}">
<Button.Template>
<ControlTemplate>
<StackPanel HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Background="#0099cc"
Orientation="Vertical"
Padding="5">
<TextBlock HorizontalAlignment="Center"
FontFamily="Segoe MDL2 Assets"
FontSize="25"
Text="" />
<TextBlock HorizontalAlignment="Center" Text="Save" />
</StackPanel>
</ControlTemplate>
</Button.Template>
</Button>
</StackPanel>
</ScrollViewer>
</Grid>
DateOffset转换器的代码：
public class DateTimetoDateTimeOffsetConverter : IValueConverter { public object Convert(object value,Type targettype,object parameter,string language) { try { if (value is DateTime) { DateTime date = (DateTime)value; return new DateTimeOffset(date); } else return new DateTimeOffset(DateTime.Now); } catch (Exception ex) { return new DateTimeOffset(DateTime.Now); } } public object ConvertBack(object value,string language) { DateTimeOffset dto = (DateTimeOffset)value; return dto.DateTime; } }
TimeOffset转换器的代码：
public class DateTimetoTimeSpanConverter : IValueConverter { public object Convert(object value,string language) { try { if (value is DateTime) { DateTime date = (DateTime)value; return new TimeSpan(date.Ticks); } else return new TimeSpan(DateTime.Now.Ticks); } catch (Exception ex) { return new TimeSpan(DateTime.Now.Ticks); } } public object ConvertBack(object value,string language) { TimeSpan ts = (TimeSpan)value; DateTime dt = new DateTime(ts.Ticks); return dt; } }
鉴于调试器中断的代码,错误似乎是在xaml端,正如我所说,删除日期和时间选择器,这是绑定使用自定义转换器的唯一元素,似乎解决它.
我错过了什么？
UPDATE
进一步的测试引起了我的注意,删除自定义转换器实际上并没有解决问题,它只是增加了导航的数量,直到错误发生.我已经尝试完全删除绑定仍然得到错误.删除每个元素,但调用下一页的按钮似乎工作,但此时我无法确定它是否实际修复了问题或只是缓解了它.
解决方法
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