WPF / MVVM-标题绑定

Question

I'm using MVVM pattern in WPF. My small project contains 1x Window and 3x UserControls. Each UserControl represents tab, please see the picture below.

Solution structure

What I'm trying to do is to bind the Window Title to the variable in each tab model. I tried to use Interaction.Triggers and event name "Loaded". The command "ChangeTitle" works fine when I switch between different views but when I select tab with the same view as previously selected tab then title doesn't change until I switch to another tab with different view. I tried other events but couldn't find any for this purpose. I would like to trigger the above command after tab selection changed. Please advise. Thank you.

MainWindow.xaml

<Window x:Class="LSS_doc.Views.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:intr="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
    xmlns:models="clr-namespace:LSS_doc.Models"
    xmlns:Views="clr-namespace:LSS_doc.Views"
    mc:Ignorable="d"
    Height="350" Width="525"
    MinHeight="350"
    MinWidth="525">

<Grid>
    <intr:Interaction.Triggers>
        <intr:EventTrigger EventName="Loaded">
            <intr:InvokeCommandAction Command="{Binding CreateMainTab}"/>
        </intr:EventTrigger>
    </intr:Interaction.Triggers>
    <DockPanel>
        <TabControl Name="tabControl" ItemsSource="{Binding Tabs}" SelectedIndex="{Binding TabIndex}">
            <TabControl.Resources>
                <DataTemplate DataType="{x:Type models:MainTabModel}">
                    <Views:MainTabView/>
                </DataTemplate>
                <DataTemplate DataType="{x:Type models:ResultTabModel}">
                    <Views:ResultTabView/>
                </DataTemplate>
                <DataTemplate DataType="{x:Type models:DisplayTabView}">
                    <Views:DisplayTabView/>
                </DataTemplate>
            </TabControl.Resources>

            <TabControl.ItemTemplate>
                <DataTemplate DataType="{x:Type models:ITabModel}">
                    <TextBlock>
                    <Run Text="{Binding Name}"/>
                    <Hyperlink Command="{Binding CloseCommand}" ><Run Text="{Binding CloseButton}"/></Hyperlink>
                    </TextBlock>
                </DataTemplate>
            </TabControl.ItemTemplate>
        </TabControl>
    </DockPanel>
</Grid>

MainTabView.xaml

<UserControl x:Class="LSS_doc.Views.MainTabView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:intr="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
         mc:Ignorable="d"

         d:DesignHeight="450" d:DesignWidth="800">
<intr:Interaction.Triggers>
    <intr:EventTrigger EventName="Loaded">
        <intr:InvokeCommandAction CommandParameter="{Binding Name}" Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.ChangeTitle}"/>
    </intr:EventTrigger>
</intr:Interaction.Triggers>
<Grid>

    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="100"/>
    </Grid.ColumnDefinitions>
    <Grid.RowDefinitions>
        <RowDefinition Height="50"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <TextBox Name="searchBox" Text="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.Keywords}" Margin="10,10,10,10" Height="30"/>
    <Button Name="searchButton" Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.Search}" Grid.Column="1" Margin="0,0,10,0" Height="30"/>
    <TreeView Grid.Row="1" Grid.ColumnSpan="2" Margin="10,0,10,10" BorderThickness="0">
        <TreeViewItem Header="{Binding Name}" IsExpanded="True">
            <TreeViewItem Header="Level 2.1" />
            <TreeViewItem Header="Level 2.2" IsExpanded="True">
                <TreeViewItem Header="Level 3.1" />
                <TreeViewItem Header="Level 3.2" />
            </TreeViewItem>
            <TreeViewItem Header="Level 2.3" />
        </TreeViewItem>
    </TreeView>
</Grid>

ResultTabView.xaml

<UserControl x:Class="LSS_doc.Views.ResultTabView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:intr="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" 
         d:DesignHeight="450" d:DesignWidth="800">
<intr:Interaction.Triggers>
    <intr:EventTrigger EventName="Loaded">
        <intr:InvokeCommandAction CommandParameter="{Binding Name}" Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.ChangeTitle}"/>
    </intr:EventTrigger>
</intr:Interaction.Triggers>
<Grid>
    <ListBox x:Name="FileList" ItemsSource="{Binding Result}">
        <ListBox.ItemTemplate>
            <DataTemplate DataType="string">
                <TextBlock>
                    <Hyperlink CommandParameter="{Binding}" Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.DisplayFile}">
                        <TextBlock Text="{Binding}"/>
                    </Hyperlink>
                </TextBlock>
            </DataTemplate>
        </ListBox.ItemTemplate>
    </ListBox>
</Grid>

DisplayTabView.xaml

<UserControl x:Class="LSS_doc.Views.DisplayTabView"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:intr="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         xmlns:local="clr-namespace:LSS_doc.Helpers"
         xmlns:ns="clr-namespace:LSS_doc.Helpers"
         mc:Ignorable="d" 
         d:DesignHeight="450" d:DesignWidth="800">
<intr:Interaction.Triggers>
    <intr:EventTrigger EventName="Loaded">
        <intr:InvokeCommandAction CommandParameter="{Binding Name}" Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}, Path=DataContext.ChangeTitle}"/>
    </intr:EventTrigger>
</intr:Interaction.Triggers>
<Grid >
    <WebBrowser local:WebBrowserExtensions.BindableSource="{Binding FileUrl}" local:WebBrowserExtensions.BindableLoaded="{Binding AcceptedKeywords}"/>
</Grid>

Answer 1

您可以使用ElementName将窗口标题直接绑定到模型：

<Window Title="{Binding ElementName=tab,Path=SelectedItem.WindowTitleForThisTab}">