ListView绑定到一个集合，如何访问父类中的事件？
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【中文标题】ListView绑定到一个集合，如何访问父类中的事件？【英文标题】：ListView binds to a collection, how to access an event in a parent class? 【发布时间】：2017-07-01 15:40:57 【问题描述】：在我的 WinRT 项目中，我有一个 ListView，如下所示；
<ListView Grid.Row="1"
ItemsSource="Binding Path=Survey.SelectedSection.QuestionsAndNavigation, Mode=TwoWay"
IsSwipeEnabled="False"
SelectionMode="None"
ScrollViewer.VerticalScrollBarVisibility="Auto"
Background="White"
ItemTemplateSelector="StaticResource ResourceKey=QuestionDisplay"
ItemContainerStyle=
"StaticResource ResourceKey=QuestionListViewItemContainerStyle">
</ListView>
注意这一行； ItemsSource="绑定路径=Survey.SelectedSection.QuestionsAndNavigation" 集合 QuestionsAndNavigation 以 UserControl 中的一些导航按钮结尾；
<StackPanel Orientation="Horizontal" >
<Button Margin="0,40,40,0"
IsEnabled="Binding Path=PreviousSectionId, Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding Path=NavigateToPreviousSectionCommand"><< Save and Previous Section</Button>
<Button Margin="0,40,0,0"
IsEnabled="Binding Path=NextSectionId, Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding Path=NavigateToNextSectionCommand">Save and Next Section >></Button>
</StackPanel>
并显示如下；
现在的问题是在绑定路径中：Survey.SelectedSection.QuestionsAndNavigation 我希望该命令位于伟大的 GrandParent 类 SurveyPageViewModel（其中包含调查对象）中，而不是嵌入集合类 QuestionsAndNavigation 中。默认情况下，数据上下文在错误的类中查找。 重要的是要认识到这不是继承。此处的“Survey”映射到 SurveyPageViewModel 类，该类包含映射到 SurveyViewModel 类的 Survey，映射到 SectionViewModel 类的 SelectedSection，并且包含 QuestionsAndNavigation，它是 QuestionViewModel 类的集合。
所以 QuestionViewModel 中的代码：
private void NavigateToNextSection()
NavigateToSection(this.NextSectionId);
private void NavigateToPreviousSection()
NavigateToSection(this.PreviousSectionId);
private void NavigateToSection(int sectionId)
NavService.Navigate("NewSection", sectionId);
没有转到 SurveyPageViewModel，我无法在 QuestionViewModel 类中设置 NavService，因为它不存在，而是 SurveyPageViewModel 中的一个属性。
编辑。 所以感谢 Eric 的回答，我的 ListView 包含一个 x:Name = "ListResponses"。我在按钮的路径中使用它：
<StackPanel Orientation="Horizontal" >
<Button Margin="0,40,40,0"
IsEnabled="Binding Path=PreviousSectionId,
Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding
Path=DataContext.SaveThenPreviousSectionCommand,
ElementName=ListResponses"><< Previous Section</Button>
<Button Margin="0,40,0,0"
IsEnabled="Binding Path=NextSectionId,
Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding
Path=DataContext.SaveThenNextSectionCommand,
ElementName=ListResponses">Next Section >></Button>
</StackPanel>
我已将事件连接放在 SurveyPageViewModel 中，但由于某种我想知道答案的原因，它们没有连接起来；
public ICommand SaveThenPreviousSectionCommand get; private set;
public ICommand SaveThenNextSectionCommand get; private set;
... （在构造函数中）
SaveThenPreviousSectionCommand = new DelegateCommand(DoSaveThenPreviousSection);
SaveThenNextSectionCommand = new DelegateCommand(DoSaveThenNextSection);
...
private async void DoSaveThenPreviousSection()
var i = 1;
private async void DoSaveThenNextSection()
var i = 0;
编辑：这是页面的完整 XAML 文件
<prism:VisualStateAwarePage x:Class="M.Survey.Views.SurveyPage"
x:Name="pageRoot"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:views="using:M.Survey.Views"
xmlns:local="using:M.Survey"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:prism="using:Microsoft.Practices.Prism.StoreApps"
xmlns:mvvm="using:Microsoft.Practices.Prism.Mvvm"
mvvm:ViewModelLocator.AutoWireViewModel="true"
xmlns:userControls="using:M.Survey.UserControls"
mc:Ignorable="d"
xmlns:converters="using:M.Survey.Converters"
Loaded="pageRoot_Loaded"
Unloaded="pageRoot_Unloaded"
xmlns:templateSelectors="using:M.Survey.TemplateSelectors">
<prism:VisualStateAwarePage.Resources>
<ResourceDictionary>
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary Source="/Themes/AllQuestionDataTemplates.xaml" />
<ResourceDictionary Source="/Themes/Styles.xaml" />
<ResourceDictionary Source="/Themes/DataTemplates.xaml" />
</ResourceDictionary.MergedDictionaries>
<templateSelectors:QuestionTemplateSelector x:Key="QuestionDisplay"
TextEntry="StaticResource TextEntry"
DateTimeEntry="StaticResource DateTimeEntry"
BoolEntry="StaticResource BoolEntry"
IntEntry="StaticResource IntEntry"
SelectEntry="StaticResource SelectEntry"
DecimalEntry="StaticResource DecimalEntry"
LargeTextArea="StaticResource LargeTextArea"
SorEntry="StaticResource SorEntry"
Additional="StaticResource AdditionalEntry"
Miscellaneous="StaticResource Miscellaneous"
Dim="StaticResource Dim"
Signature="StaticResource Signature"
SectionNavigation="StaticResource SectionNavigation"/>
<converters:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
<converters:InverseBooleanConverter x:Key="InverseBooleanConverter" />
</ResourceDictionary>
</prism:VisualStateAwarePage.Resources>
<Grid>
<Grid.Background>
<SolidColorBrush Color="StaticResource ResourceKey=AppBackgroundColor" />
</Grid.Background>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="80" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid Grid.Row="0" Background="StaticResource ResourceKey=MulalleyBlueBrush">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<StackPanel Orientation="Horizontal" Margin="20, 0, 0, 5">
<Button Margin="0, 0, 15, 0" Command="Binding Path=TryGoHomeCommand" Style="StaticResource BackButtonStyle" />
<TextBlock Style="StaticResource ResourceKey=MediumHeaderTextBlockStyle" Text="Binding Path=Job.ShortDisplayAddress" VerticalAlignment="Bottom" />
<StackPanel Margin="40, 0, 0, 6" Width="30" VerticalAlignment="Bottom" Height="30">
<ProgressRing Height="30" Width="30" Foreground="White" IsActive="Binding Path=WorkInProgress" Visibility="Binding Path=WorkInProgress, Converter=StaticResource ResourceKey=BooleanToVisibilityConverter" />
</StackPanel>
<TextBlock Margin="10, 0, 0, 10" VerticalAlignment="Bottom" Text="Binding Path=FeedbackMsg" Style="StaticResource ResourceKey=SmallHeaderTextBlockStyle" />
</StackPanel>
<Grid Margin="0, 0, 15, 5" Grid.Column="1" VerticalAlignment="Bottom">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<TextBlock VerticalAlignment="Bottom" Text="Internet" Style="StaticResource ResourceKey=MediumHeaderTextBlockStyle" />
<TextBlock Margin="10, 0, 15, 6" VerticalAlignment="Bottom" Grid.Column="1" Text="Binding Path=ConnectionStatus" Style="StaticResource ResourceKey=SmallHeaderStyle" />
<TextBlock VerticalAlignment="Bottom" Text="Server" Style="StaticResource ResourceKey=MediumHeaderTextBlockStyle" Grid.Column="2" />
<TextBlock Margin="10, 0, 15, 6" VerticalAlignment="Bottom" Grid.Column="3" Text="Binding Path=***Status" Style="StaticResource ResourceKey=SmallHeaderStyle" />
<TextBlock VerticalAlignment="Bottom" Text="User" Style="StaticResource ResourceKey=MediumHeaderTextBlockStyle" Grid.Column="4" />
<TextBlock Margin="10, 0, 0, 6" VerticalAlignment="Bottom" Grid.Column="5" Text="Binding Path=User.DisplayName" Style="StaticResource ResourceKey=SmallHeaderStyle" />
</Grid>
<TextBlock Width="80" Margin="100, 0, 30, 0" Text="Binding Path=AnswersCompleteDisplay" Grid.Column="1" Style="StaticResource ResourceKey=MediumHeaderTextBlockStyle"/>
<Button Style="StaticResource ResourceKey=SaveButtonStyle" Content="Save" Grid.Column="2" Command="Binding Path=SaveCommand" />
</Grid>
</Grid>
<Grid Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="2*" />
</Grid.ColumnDefinitions>
<Grid>
<Grid.Background>
<SolidColorBrush Color="StaticResource ResourceKey=MulalleyBlue" Opacity=".2" />
</Grid.Background>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<ListView
ItemsSource="Binding Path=Survey.Sections, Mode=TwoWay"
SelectedItem="Binding Path=Survey.SelectedSection, Mode=TwoWay"
IsSwipeEnabled="False"
SelectionMode="Single"
ItemContainerStyle="StaticResource ResourceKey=ListViewItemContainerStyle"
ItemTemplate="StaticResource ResourceKey=SurveySectionDataTemplate"
ScrollViewer.HorizontalScrollBarVisibility="Hidden"
ScrollViewer.VerticalScrollBarVisibility="Auto"
/>
</Grid>
<Grid Grid.Column="1" Margin="30, 30, 15, 20">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<StackPanel Grid.Row="0" Orientation="Horizontal">
<TextBlock Text="*" FontSize="40" FontWeight="Bold" Foreground="Red"/>
<TextBlock Text=" = Required " FontSize="20"/>
</StackPanel>
<ListView
x:Name="ListResponses"
Grid.Row="1"
ItemsSource="Binding Path=Survey.SelectedSection.QuestionsAndNavigation, Mode=TwoWay"
IsSwipeEnabled="False"
SelectionMode="None"
ScrollViewer.VerticalScrollBarVisibility="Auto"
Background="White"
ItemTemplateSelector="StaticResource ResourceKey=QuestionDisplay"
ItemContainerStyle=
"StaticResource ResourceKey=QuestionListViewItemContainerStyle">
</ListView>
</Grid>
</Grid>
</Grid>
</Grid>
<userControls:SurveyDialogUserControl />
<userControls:SurveyReassignedDialogUserControl />
<userControls:CopyFromUserControl />
</Grid>
<prism:VisualStateAwarePage.BottomAppBar>
<CommandBar Name="commandBar">
<CommandBar.SecondaryCommands>
<AppBarButton Label="Settings" Icon="Setting" Click="AppBarButton_Click" />
<AppBarButton Label="Log" Icon="Admin" Click="LogButton_Click" />
<AppBarButton Label="Refresh" Icon="Refresh" Command="Binding Path=RefershAllDataCommand" IsEnabled="Binding Path=WorkInProgress, Converter=StaticResource ResourceKey=InverseBooleanConverter" Visibility="Binding Path=***Online, Converter=StaticResource ResourceKey=BooleanToVisibilityConverter" />
<AppBarButton Label="Copy From" Icon="Copy" Click="CopyButton_Click" Command="Binding Path=ShowCopyFromCommand" IsEnabled="Binding Path=WorkInProgress, Converter=StaticResource ResourceKey=InverseBooleanConverter" />
</CommandBar.SecondaryCommands>
</CommandBar>
</prism:VisualStateAwarePage.BottomAppBar>
</prism:VisualStateAwarePage>
这是用户控件 XAML；
<UserControl
x:Class="M.Survey.UserControls.SectionNavigation"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:M.Survey.UserControls"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:converters="using:M.Survey.Converters"
mc:Ignorable="d"
d:DesignHeight="30"
d:DesignWidth="400">
<UserControl.Resources>
<ResourceDictionary>
<converters:IntBooleanConverter x:Key="IntBooleanConverter" />
</ResourceDictionary>
</UserControl.Resources>
<Grid>
<StackPanel Orientation="Horizontal" >
<Button Margin="0,40,40,0"
IsEnabled="Binding Path=PreviousSectionId,
Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding
Path=DataContext.SaveThenPreviousSectionCommand,
ElementName=ListResponses"><< Previous Section</Button>
<Button Margin="0,40,0,0"
IsEnabled="Binding Path=NextSectionId,
Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding
Path=DataContext.SaveThenNextSectionCommand,
ElementName=ListResponses">Next Section >></Button>
</StackPanel>
</Grid>
</UserControl>
【问题讨论】：
【参考方案1】：假设 ListView XAML 与 Button XAML 位于同一文件中（并且 ListView 为 x:Name="listView"）：
<Button Margin="0,40,0,0"
IsEnabled="Binding Path=NextSectionId, Converter=StaticResource ResourceKey=IntBooleanConverter"
Command="Binding ElementName=listView, Path=DataContext.Survey.DESIRED_COMMAND">Save and Next Section >></Button>
此外，您还可以在实例化时将调查视图模型的实例传递给问题视图模型（取决于您创建视图模型的方式）。
最后，您还可以使用事件发布系统（例如 MVVM Light Messenger）在单击调查连接以响应的按钮时发布事件。
【讨论】：
我确信您的回答是正确的，但我无法将其连接起来。当我单击按钮时，没有任何反应。顺便说一句，我对 ViewModel 树的看法是错误的。 SurveyPageViewModel 包含 1 个 SurveyViewModel，其中包含 1 个 SelectedSection，其中包含 QuestionViewModel 对象的集合。命令事件在 SurveyPageViewModel 类上。所以对我来说有意义的是，在识别 ListView 的名称时，然后在按钮“Path=DataContext.DESIRED_COMMAND”中。 Button 位于 UserControl 文件中，而不是与 LIstView 位于同一文件中。是这个问题吗？ 顺便将 SurveyPageViewModel 的引用传递给 QuestionViewModel 会创建一个循环引用，所以我认为这行不通。而且我不熟悉 MVVM Light Messenger。我查了一下，但对我来说看起来很复杂（我是 XAML 新手） 我已经更新了我的答案，所以你可以看到我做了什么。 您能否发布完整的 XAML 文件，以便我查看哪些项目在彼此的范围内？ 好的。我曾认为 ListView 和按钮在同一范围内（或至少是文件）。 XAML ElementName 绑定不起作用。我最好的建议是使用像 MVVM Light Messenger 类 (msdn.microsoft.com/en-us/magazine/jj694937.aspx) 这样的 pub sub。【参考方案2】：我从 Eric 那里得到了很多帮助，他给出了另一个答案。 为了在嵌入在它们自己的复杂设计中的 2 个类之间进行通信，一种方法是使用 EventAggregator 模式。碰巧我正在开发的应用程序使用 Prism，它是 EventAggregator 自己的实现。此模式使您能够发布有效负载，该有效负载由接收类上的订阅事件拾取。
【讨论】：
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