我有一个ListView的问题。设置为ItemsSource的 <body>
<button onclick="myFunction()">Yes</button>
<div id="myDIV">
Can someone please help me?
</div>
<script>
function myFunction() {
var x = document.getElementById("myDIV");
if (x.style.display === "none") {
x.style.display = "block";
} else {
x.style.display = "none";
}
}
</script>
</body>
时，应用程序会冻结几秒钟。
这是列表视图：
new Scaffold(
appBar: new AppBar(
automaticallyImplyLeading: false,
)
)
这是填充条目列表的方法：
ObservableCollection我确信没有CPU绑定操作，只有在分配了 <UserControl.Resources>
<CollectionViewSource x:Key="Sets" Source="{Binding Path=Entries}">
<CollectionViewSource.GroupDescriptions>
<PropertyGroupDescription PropertyName="DailySet.WeeklySet" />
<PropertyGroupDescription PropertyName="DailySet" />
</CollectionViewSource.GroupDescriptions>
</CollectionViewSource>
<utilities:InvertableBooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</UserControl.Resources>
<ListView ItemsSource="{Binding IsAsync=True, UpdateSourceTrigger=PropertyChanged}" DataContext="{StaticResource Sets}" >
<ListView.View >
<GridView >
<GridViewColumn DisplayMemberBinding="{Binding StartTimeFormatted}" Header="Start" Width="60" />
<GridViewColumn DisplayMemberBinding="{Binding EndTimeFormatted}" Header="End" Width="60" />
<GridViewColumn DisplayMemberBinding="{Binding TotalHoursFormatted}" Header="Time" Width="80" />
<GridViewColumn DisplayMemberBinding="{Binding CostCode}" Header="CostCode" Width="120" />
<GridViewColumn DisplayMemberBinding="{Binding Operation}" Header="Operation" Width="160" />
<GridViewColumn DisplayMemberBinding="{Binding Comment}" Header="Comment" >
<GridViewColumn.Width>
<MultiBinding Converter="{StaticResource LastColumnMaximizerConverter}">
<Binding Path="ActualWidth"
RelativeSource="{RelativeSource AncestorType=ListView}"/>
<Binding Path="View.Columns"
RelativeSource="{RelativeSource AncestorType=ListView}"/>
</MultiBinding>
</GridViewColumn.Width>
</GridViewColumn>
<GridViewColumn Header="Action" Width="60">
<GridViewColumn.CellTemplate>
<DataTemplate >
<StackPanel Orientation="Horizontal" >
<Button IsEnabled="{Binding ElementName=thisUc, Path=DataContext.EditingAllowed}"
BorderThickness="0" Margin="2" VerticalAlignment="Center" HorizontalAlignment="Center" Background="Transparent" ToolTip="Edit this entry"
Command="{Binding ElementName=thisUc, Path=DataContext.EditEntryCommand}" CommandParameter="{Binding}">
<Button.Content>
<Image Height="18" Width="20" Source="pack://application:,,,/Gfx/edit.png"></Image>
</Button.Content>
</Button>
<Button IsEnabled="{Binding ElementName=thisUc, Path=DataContext.EditingAllowed}" BorderThickness="0" Margin="2" VerticalAlignment="Center" HorizontalAlignment="Center" Background="Transparent" ToolTip="Delete this entry"
Command="{Binding ElementName=thisUc, Path=DataContext.DeleteEntryCommand}" CommandParameter="{Binding}">
<Button.Content>
<Image Height="18" Width="20" Source="pack://application:,,,/Gfx/delete.png"></Image>
</Button.Content>
</Button>
</StackPanel>
</DataTemplate>
</GridViewColumn.CellTemplate>
</GridViewColumn>
</GridView>
</ListView.View>
<ListView.GroupStyle>
<GroupStyle>
<GroupStyle.ContainerStyle>
<Style TargetType="{x:Type GroupItem}">
<Setter Property="Margin" Value="0,0,0,5"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type GroupItem}">
<Expander IsExpanded="{Binding Path=Name.IsWeekOpen, Mode=OneWay}" >
<Expander.Header>
... header label definition
</Expander.Header>
<Expander.Content>
<ItemsPresenter />
</Expander.Content>
</Expander>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupStyle.ContainerStyle>
</GroupStyle>
<GroupStyle>
<GroupStyle.ContainerStyle>
<Style TargetType="{x:Type GroupItem}">
<Setter Property="Margin" Value="10,0,10,5"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type GroupItem}">
<Expander IsExpanded="False" BorderBrush="#FFA4B97F"
BorderThickness="0,0,0,1" IsEnabled="{Binding Path=Name.DayDetailsGroupingHeader.RealEntriesAvailable}">
<Expander.Header>
... header label definition
</Expander.Header>
<Expander.Content>
<ItemsPresenter />
</Expander.Content>
</Expander>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</GroupStyle.ContainerStyle>
</GroupStyle>
</ListView.GroupStyle>
</ListView>
集合时才会出现问题。
我尝试用空集合替换public override async Task LoadLiveData()
{
IEnumerable<DailyDetailedInfo> details = await this.Connector.GetDetails();
List<DailyDetailEntry> entries = this.Mapper.Map<IEnumerable<DailyDetailedInfo>, IEnumerable<DailyDetailEntry>>(details).ToList();
//up to this point the execution takes ~300-500 miliseconds
this.Entries = new ObservableCollection<DailyDetailEntry>(entries.OrderBy(x => x.ExtractedStartDate));
// collection assigning takes few miliseconds as well
//this.Entries = new ObservableCollection<DailyDetailEntry>(); when empty collection is assigned, the UI is not frozen, even though the Connector.GetDetails() is called
}
赋值，在这种情况下它可以正常工作。
我也尝试逐个添加项目，但没有变化：
this.Entries我应该怎么做才能让用户界面响应？