在应用于 TabItem 的 DataTemplate 中查找元素 [英] Find an element in DataTemplate applied to TabItem

问题描述

我在尝试查找在 DataTemplate 中声明的元素时遇到问题，该元素之后像 ContentTemplate 一样应用于 TabItem 对象.我看到已经有一些关于这个问题的解决方案，但没有一个真正适用于我的情况，我想了解原因(显然我在某些地方犯了错误)这是一个示例代码:

I got a problem trying to find an element declared in DataTemplate, that after was applied like a ContentTemplate to TabItem object. I saw that there is already some solutions in regard of this problem, but no one of them actually works in my case, and I would like to understand why (obviously I make mistake in some place) Here is a sample code:

<DataTemplate x:Key="TabItemDataTemplate">             
    <Grid HorizontalAlignment="Stretch" 
        VerticalAlignment="Stretch" Name="templateGrid">
        <Grid.RowDefinitions>
            <RowDefinition Height="6.0*"> </RowDefinition>
            <RowDefinition Height="6" ></RowDefinition>
            <RowDefinition Height="6.0*" ></RowDefinition>
            <RowDefinition Height="*" ></RowDefinition>
        </Grid.RowDefinitions>                

        <ListView x:Name="repoView" Grid.Row="0" 
            VerticalAlignment="Stretch"
            ItemsSource="{Binding Source={StaticResource  DataProviderForListView}}">                        
            <GridView>
                <GridViewColumn Header="State"
                    DisplayMemberBinding="{Binding Path=RepositoryItemState}"/>
                <GridViewColumn Header="Working Copy Rev num."
                    DisplayMemberBinding="{Binding Path=WCRevision}"/>
                <GridViewColumn Header="Repository Rev num."
                    DisplayMemberBinding="{Binding Path=RepoRevision}"/>
                <GridViewColumn Header="User"
                    DisplayMemberBinding="{Binding Path=Account}"/>
                <GridViewColumn Header="Item"
                    DisplayMemberBinding="{Binding Path=ItemName}"/>
            </GridView>
        </ListView>

        <GridSplitter x:Name="gridSplitter" Grid.Row="1"
            ResizeDirection="Rows" Background="Gray" 
            Height="4" HorizontalAlignment="Stretch"
            Style="{StaticResource gridSplitterStyle}"/>

        <RichTextBox x:Name="rowView" Grid.Row="2" 
            BorderBrush="Bisque" VerticalAlignment="Stretch"
            IsReadOnly="True" Background="YellowGreen"
            FontFamily="Comic Sans Serif"/>


        <ToggleButton x:Name="rbWorkingCopy"
            Template="{StaticResource ToggleButtonControlTemplate}"
            Grid.Row="3" Width="100" Height="22"
            Content="{StaticResource WorkingCopyTitle}"
            HorizontalAlignment="Left" VerticalAlignment="Bottom"
            Command="repoManager:AppCommands.GetWorkingCopyInfoCommand" />
        <ToggleButton x:Name="rbRepository"
            Template="{StaticResource ToggleButtonControlTemplate}"
            Grid.Row="3"  Width="100" Height="22"
            Content="{StaticResource  RepositoryTitle}"
            HorizontalAlignment="Left"
            VerticalAlignment="Bottom"  Margin="120,0,0,0" 
            Command="repoManager:AppCommands.GetRepoInfoCommand" />
        <ProgressBar x:Name="checkRepositoryProgress" Grid.Row="3"
            Width="220" Height="22" HorizontalAlignment="Right"  
            VerticalAlignment="Bottom" Margin="250,0,10,0"
            IsIndeterminate="True"
            IsEnabled="{Binding repoManager:ExecutingCommand}"  />
    </Grid>
</DataTemplate>

此代码通过以下方式以编程方式应用于给定的 TabItem 对象:

This code is porgrammatically applied to the given TabItem object in following way :

this.ContentTemplate = FindResource("TabItemDataTemplate") as DataTemplate;

在我需要访问在 DataTemplate 中声明的 ListView 元素之后，我执行了在 Internet 上以及在此站点上找到的代码.这是一个简短的例子:

After I need access to the ListView element declared in DataTemplate, so I execute the codes found around in internet, and also on this site. Here is a short example:

/* Getting the ContentPresenter of myListBoxItem*/          
ContentPresenter myContentPresenter =
    FindVisualChild<ContentPresenter>(this);

// this.GetVisualChild(0)
/* Finding textBlock from the DataTemplate that is set on that ContentPresenter*/
DataTemplate myDataTemplate = myContentPresenter.ContentTemplate;

ListView repoListView = (ListView)myDataTemplate.FindName("repoView", 
    myContentPresenter);

问题 1:此时 ContentPresenter 的 ContentTemplate 为 Null，因此代码执行崩溃.Prolem2:好的，我想，可能是我需要直接导航 throw TabItem 内容，所以代码或多或少变成了:

Problem1: In this case ContentTemplate of ContentPresenter is Null, so code execution crashes. Prolem2: Ok, I think, may be I need to navigate throw TabItem content directly, so the code becomes, more or less:

/* Getting the ContentPresenter of myListBoxItem*/          
ContentPresenter myContentPresenter =
    FindVisualChild<ContentPresenter>(this);

// this.GetVisualChild(0)
/* Finding textBlock from the DataTemplate that is set on that ContentPresenter*/
DataTemplate myDataTemplate = this.ContentTemplate;

ListView repoListView = (ListView)myDataTemplate.FindName("repoView", 
    myContentPresenter);

this 是 TabItem 对象.但奇怪的是，this 的 ContentTemplate 与上面分配的完全不同.我确定我在某个地方遗漏了一些东西，你能帮我找出问题所在吗?谢谢.

this is TabItem object. But the strage things, that the ContentTemplate of this is completely different from that one assigned above. I'm sure that I missed something somewhere, can you help me to figure out the problem ? Thank you.

推荐答案

好的，我们来了 :)我以不是很好的方式解决了这个问题，但似乎可以正常工作.正如我上面提到的，我使用了 LoadContent 方法，它返回了 ListView 对象，但顺便说一下，它不是 UI 实际使用的 ListView.因此，为了解决这个问题，我添加了静态属性来保存我的 REAL ListView 对象(静态的，因为我有单个 DataTemplate，其中包含跨多个 TabItem 共享的 ListView，所以 ListView 也共享)并将事件处理程序添加到我的 DataTemplate -> Loaded.捕获此事件，在我的情况下，仅在应用程序的生命周期中引发事件，在 RoutedEvent's OriginalSource 中，我得到了 WPF 引擎用于在 UI 上呈现的 REAL ListView 对象.希望我的解决方案对某人有所帮助.谢谢大家.

Ok, here we come :) I resolve the problem, in not very nice way, but it seems that works correctly. As I mentioned above I used LoadContent method and it returns me the ListView object, but by the way it wasn't the ListView that UI actually uses. So to resolve that problem I add static property to hold my REAL ListView object (static as I have single DataTemplate that contains ListView shared across multiple TabItems, so the ListView shared too) and add event handler to my DataTemplate -> Loaded. Catching this event, that in my case raises only ones in lifetime of application, in RoutedEvent's OriginalSource I got the REAL ListView object that WPF engine uses for rendering on UI. Hope my solution will help someone. Thank you all.

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