如何在 TabControl WPF 中获取 TabItem 标题的宽度

Question

我需要做的是在远远超出之前停止 GridSplitter，从而隐藏 TabControl。因此，我想到的想法是将 TabItems 的所有 Headers 的 ActualWidths 总和绑定到 TabControl 的 MinWidth 或保留 TabControl 的 Crid Cell。但问题是到目前为止我无法访问 TabItem 的 Header 的宽度。我发现的一个解决方案是在 Tabitem.Header 中放置一个 TextBlock，声明它的宽度并用 x:Name 命名。但是以这种方式使用宽度并不会给出包含边距和填充等在内的页眉的总宽度，因此它甚至不能接近准确度。

更新

好吧，这里是代码。请注意，我已经实现了其中一种解决方案，但如果标签是动态加载的，它不会控制 MinWidth。

<Grid Background="#FFD6DBE9" Height="614" Width="1109">
        <Grid.RowDefinitions>
            <RowDefinition Height="89"/>
            <RowDefinition Height="Auto" MinHeight="{Binding ActualHeight, ElementName=gridNotificationsHeader}"/>
            <RowDefinition Height="494*"/>
        </Grid.RowDefinitions>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="400*" MinWidth="{Binding MinWidth, ElementName=tabDataEntities}"/>
            <ColumnDefinition Width="Auto"/>
            <ColumnDefinition Width="144*">
                <ColumnDefinition.MinWidth>
                    <MultiBinding Converter="{StaticResource StringSumtoIntConvert}">
                        <Binding ElementName="cdLblNotificationsHeader" Path="MinWidth"/>
                        <Binding ElementName="cdBtnNotificationsClose" Path="ActualWidth"/>
                    </MultiBinding>
                </ColumnDefinition.MinWidth>
            </ColumnDefinition>

        </Grid.ColumnDefinitions>
        <GridSplitter x:Name="gridSplitter" Grid.Column="1" HorizontalAlignment="Center" Grid.Row="1" Width="2" Grid.RowSpan="2"/>
        <Grid x:Name="gridNotificationsHeader" Grid.Column="2" Background="#FF657695" 
          Grid.Row="1">
            <Grid.ColumnDefinitions>
                <ColumnDefinition x:Name="cdLblNotificationsHeader" MinWidth="{Binding Width, ElementName=lblNotificationsHeader}"/>
                <ColumnDefinition x:Name="cdBtnNotificationsClose" Width="Auto"/>
            </Grid.ColumnDefinitions>
            <Label x:Name="lblNotificationsHeader" Content="Notifications" VerticalAlignment="Top" 
               FontSize="14.667" Height="30" Foreground="#FFEBF0EE" HorizontalAlignment="Left" Width="92"/>
            <Button x:Name="btnNotificationsClose" Content="X" 
                Margin="0,5,8,0" VerticalAlignment="Top" Width="20" FontFamily="Verdana" HorizontalAlignment="Right" Background="Transparent" FontSize="13.333" Foreground="Black" Grid.Column="1"/>
        </Grid>
        <TabControl x:Name="tabDataEntities" Margin="0,0,5,10" Grid.Row="1" Grid.RowSpan="2" FontSize="12" Grid.ColumnSpan="1" MinWidth="{Binding ElementName=TabItemOne, Path=ActualWidth}">
            <TabItem x:Name="TabItemOne">
                <TabItem.Header>Tab Item</TabItem.Header>
                <Grid Background="#FFE5E5E5"/>
            </TabItem>
            <TabItem Header="TabItem">
                <Grid Background="#FFE5E5E5"/>
            </TabItem>
        </TabControl>
    </Grid>

Answer 1

就这么简单

<StackPanel>
    <TabControl>
        <TabItem Header="Hello world" Name="Tab1"/>
        <TabItem Header="Hello" Name="Tab2"/>
        <TabItem Header="world" Name="Tab3"/>
    </TabControl>
    <TextBlock Text="{Binding ElementName=Tab1, Path=ActualWidth}"/>
    <TextBlock Text="{Binding ElementName=Tab2, Path=ActualWidth}"/>
    <TextBlock Text="{Binding ElementName=Tab3, Path=ActualWidth}"/>
</StackPanel>

Answer 2

刚刚完成以下AttachedProperty 有点乐趣：

XAML 用法

<TabControl question32926699:TabControlHeaderWidthWatcher.WatchHeadersWidth="true"
            question32926699:TabControlHeaderWidthWatcher.TotalHeadersWidth="{Binding TotalWidth, Mode=OneWayToSource}">
  <TabItem Header="Tab Item 1" />
  <TabItem Header="Tab Item 2" />
</TabControl>

附加属性

public class TabControlHeaderWidthWatcher
{
    private static TabControl m_tabControl;

    public static readonly DependencyProperty WatchHeadersWidthProperty = DependencyProperty.RegisterAttached(
        "WatchHeadersWidth", typeof (bool), typeof (TabControlHeaderWidthWatcher), new PropertyMetadata(default(bool), PropertyChangedCallback));

    public static void SetWatchHeadersWidth(DependencyObject element, bool value)
    {
        element.SetValue(WatchHeadersWidthProperty, value);
    }

    public static bool GetWatchHeadersWidth(DependencyObject element)
    {
        return (bool)element.GetValue(WatchHeadersWidthProperty);
    }

    public static readonly DependencyProperty TotalHeadersWidthProperty = DependencyProperty.RegisterAttached(
        "TotalHeadersWidth", typeof (double), typeof (TabControlHeaderWidthWatcher), new PropertyMetadata(default(double)));

    public static void SetTotalHeadersWidth(DependencyObject element, double value)
    {
        element.SetValue(TotalHeadersWidthProperty, value);
    }

    public static double GetTotalHeadersWidth(DependencyObject element)
    {
        return (double) element.GetValue(TotalHeadersWidthProperty);
    }

    private static void PropertyChangedCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
    {
        m_tabControl = dependencyObject as TabControl;
        if (m_tabControl == null) return;

        ((INotifyCollectionChanged)m_tabControl.Items).CollectionChanged += CollectionChanged;
    }

    private static void CollectionChanged(object sender, EventArgs eventArgs)
    {
        foreach (var item in m_tabControl.Items)
        {
            var tabItem = item as TabItem;
            if (tabItem == null) continue;

            // Unsubscribe first in case it was there previously
            tabItem.SizeChanged -= TabItemOnSizeChanged;
            tabItem.SizeChanged += TabItemOnSizeChanged;
        }
    }

    private static void TabItemOnSizeChanged(object sender, SizeChangedEventArgs sizeChangedEventArgs)
    {
        var totalWidth = 0.0;
        foreach (var item in m_tabControl.Items)
        {
            var tabItem = item as TabItem;
            if (tabItem == null) continue;

            totalWidth += tabItem.ActualWidth;
        }

        // When more than one row of tabs, the width of the TabControl is used
        var actualWidth = totalWidth > m_tabControl.ActualWidth ? m_tabControl.ActualWidth : totalWidth;
        SetTotalHeadersWidth(m_tabControl, actualWidth);
    }
}

即使您使用ItemsSource 的TabControl 动态加载选项卡，此解决方案也将起作用。 TotalHeadersWidth 将始终接收总标题宽度，除非选项卡包含在多行中。在这种情况下，它将使用 TabControl 本身的 ActualWidth，在您的情况下，它会提供我们想要的。