Question

我有一个wppf应用程序，其datacontext设置为viewmodel类的实例。一切正常，除非我需要在列表框中访问viewmodel的属性，并将datacontext设置为ViewModel类中包含的集合。在msdn上，它表示你可以使用\字符进行转义，但这对我没有用

我的代码

public class StatusBoardViewModel : INotifyPropertyChanged
   {
    OIConsoleDataContext db = new OIConsoleDataContext();

    // the collection
    private IQueryable<Issue> issues;
    public IQueryable<Issue> Issues
    {
        get 
        {
            // Lazy load issues if they have not been instantiated yet
            if (issues == null)
                QueryIssues(); // This just runs a linq query to set the property
            return issues; 
        }
        set
        {
            if (issues != value)
            {
                issues = value;
                OnPropertyChanged("Issues");
            }
        }
    }
    // The property I need to access
    private bool showDetailListItems = true;
    public bool ShowDetailListItems
    {
        get
        {
            return showDetailListItems;
        }
        set
        {
            if (showDetailListItems != value)
            {
                showDetailListItems = value;
                OnPropertyChanged("ShowDetailListItems");
            }
        }
    }
}

window1.xaml.cs中的

//instantiate the view model 
StatusBoardViewModel statusBoardViewModel = new StatusBoardViewModel();

    public Window1()
    {
        InitializeComponent();
        // setting the datacontext
        this.DataContext = statusBoardViewModel;
    }

和Xaml

    // This is in the Window1.xaml file
    <ListBox x:Name="IssueListBox"
              ItemsSource="{Binding Issues}" // Binds the listbox to the collection in the ViewModel
              ItemTemplate="{StaticResource ShowIssueDetail}" 
              IsSynchronizedWithCurrentItem="True"
              HorizontalContentAlignment="Stretch" BorderThickness="3"
              DockPanel.Dock="Top" VerticalContentAlignment="Stretch" 
              Margin="2" MinHeight="50" />

// The datatemplate from the app.xaml file
    <DataTemplate x:Key="ShowIssueDetail">
        <Border CornerRadius="3" Margin="2" MinWidth="400" BorderThickness="2" 
                BorderBrush="{Binding Path=IssUrgency, Converter={StaticResource IntToRYGBBoarderBrushConverter}}">
            <StackPanel Orientation="Vertical">
                <TextBlock Text="{Binding Path=IssSubject}" Margin="3" FontWeight="Bold" FontSize="14"/>

                <!--DataTrigger will collapse following panel for simple view-->
                 <StackPanel Name="IssueDetailPanel" Visibility="Visible" Margin="3">                     
                    <StackPanel Width="Auto" Orientation="Horizontal">
                        <TextBlock Text="Due: " FontWeight="Bold"/>
                        <TextBlock Text="{Binding Path=IssDueDate}" FontStyle="Italic" HorizontalAlignment="Left"/>
                    </StackPanel>
                    <StackPanel Width="Auto" Orientation="Horizontal">
                        <TextBlock Text="Category: " FontWeight="Bold"/>
                        <TextBlock Text="{Binding Path=IssCategory}"/>
                    </StackPanel>
                </StackPanel>

            </StackPanel>
        </Border>

        // This is where I have the issue, ShowDetailListItems is in the base class, not the collection
        <DataTemplate.Triggers>
            <DataTrigger Binding="{Binding Path=ShowDetailListItems, Mode=TwoWay}" Value="False">
                <Setter TargetName="IssueDetailPanel" Property="Visibility" Value="Collapsed"/>
            </DataTrigger>
        </DataTemplate.Triggers>
    </DataTemplate>

我已经学会了TON这样做但是这个当前的问题让我感到沮丧，谷歌，MSDN，SO或者几本书没有运气

我想我会添加这个注释：我正在学习这个以便为我的业务构建一些应用程序，我是wpf和xaml的初级者，所以我重新考虑这可能是傻事。我真的很想找到一个关于datacontexts的好教程，因为我发现的是十几个不同的“How To”，它们都完全不同。我知道我的知识中有一些大漏洞，因为当我尝试在代码隐藏，Window1.xaml和app.xaml文件中创建对我的datacontext的引用时，我最终会得到我的viewmodel类的多个实例。

Answer 1

你试过其中一种吗？

{Binding Path=ShowDetailListItems, ElementName=YourWindowName}

或

{Binding ShowDetailListItems, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}

如何在xaml中访问Collection中的基本datacontext

1 个答案: