WPF 以编程方式绑定选定的 TabItem 背景属性

Question

我想以编程方式将TabItem 的Background 属性绑定到自定义属性。到目前为止，自定义背景仅在未选择 TabItem 时应用：

TabItem 与绑定一起以编程方式生成：

Binding binding = new Binding();
binding.Source = this;
binding.Converter = this;
binding.Path = new PropertyPath("HasChanged");
binding.Mode = BindingMode.OneWay;
binding.TargetNullValue = tabItem.Background;
binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
BindingOperations.SetBinding(tabItem, TabItem.BackgroundProperty, binding);

我实现了接口IValueConverter

public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
    GradientStopCollection gradient = new GradientStopCollection();
    gradient.Add(new GradientStop(Color.FromRgb(255, 234, 199), 0));
    gradient.Add(new GradientStop(Color.FromRgb(255, 233, 194), 0.5));
    gradient.Add(new GradientStop(Color.FromRgb(255, 225, 173), 0.5));
    gradient.Add(new GradientStop(Color.FromRgb(255, 221, 163), 1));
    Brush brush = new LinearGradientBrush(gradient, 90);
    return (bool)value ? brush : null;
}

public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
    return null;
}

我如何绑定属性以影响选中的TabItem？

Answer 1

正如 mm8 在对问题的评论中提供的链接中所述，您需要覆盖 TabItem 的 ControlTemplate。下面是 TabControl 的实现，左侧有选项卡和 TabItem 的自定义 ControlTemplate。通过更改边框的粗细来突出显示选定的项目：

<TabControl TabStripPlacement="Left"  
                VerticalAlignment="Stretch"
                HorizontalContentAlignment="Stretch"
                Name="tc"
                ItemsSource="{Binding MySource, Mode=OneWay}"
                ContentTemplate="{StaticResource templateForTheContent}"
                ItemTemplate="{StaticResource templateForTheHeader}">
        <TabControl.Resources>
            <Style TargetType="TabItem">
                <Setter Property="Template">
                    <Setter.Value>
                        <ControlTemplate TargetType="TabItem">
                            <Border Name="brdPanel"
                                    CornerRadius="3,0,0,3"
                                    BorderBrush="Black"
                                    Background="{TemplateBinding Background}"
                                    Margin="2,2,0,2"
                                    BorderThickness="1,1,0,1">
                                <ContentPresenter VerticalAlignment="Center"
                                                  HorizontalAlignment="Center"
                                                  ContentSource="Header"
                                                  Margin="10,2" />
                            </Border>
                            <ControlTemplate.Triggers>
                                <Trigger Property="IsSelected"
                                         Value="True">
                                    <Setter TargetName="brdPanel"
                                            Property="BorderThickness"
                                            Value="2,2,0,2" />
                                    <Setter TargetName="brdPanel"
                                            Property="Margin"
                                            Value="1,1,0,1" />
                                </Trigger>
                                <Trigger Property="IsSelected"
                                         Value="False">
                                    <Setter TargetName="brdPanel"
                                            Property="BorderThickness"
                                            Value="1,1,0,1" />
                                    <Setter TargetName="brdPanel"
                                            Property="Margin"
                                            Value="2,2,0,2" />
                                </Trigger>
                            </ControlTemplate.Triggers>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </TabControl.Resources>
    </TabControl>

在 Background 的绑定下方手动设置为 LightCoral（此处绑定源的设置与 OP 不同，以进行演示）：

       MyItemVM myItem=this.tc.Items[0];
       TabItem tabItem = (TabItem)this.tc.ItemContainerGenerator.ContainerFromItem(myItem);

        Binding binding = new Binding();
        binding.Source = myItem;
        binding.Path = new PropertyPath("GroupBackground");
        binding.Mode = BindingMode.OneWay;
        binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
        BindingOperations.SetBinding(tabItem, TabItem.BackgroundProperty, binding);

        myItem.GroupBackground = Brushes.LightCoral;

        MyItemVM myItem=this.tc.Items[1];
        tabItem = (TabItem)this.tc.ItemContainerGenerator.ContainerFromItem(myItem);

        binding = new Binding();
        binding.Source = myItem;
        binding.Path = new PropertyPath("GroupBackground");
        binding.Mode = BindingMode.OneWay;
        binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
        BindingOperations.SetBinding(tabItem, TabItem.BackgroundProperty, binding);

       myItem.GroupBackground = Brushes.LightCoral;

结果如下所示：

注意这只会改变 TabItem 标题的背景。

Answer 2

我最终使用了 Arie 的答案的一部分，但我无法使用他的模板，因为我想要默认的 Windows Tab 样式。

我的第一步是删除所有程序生成的绑定和转换器。然后我使用TabItem 的Tag 属性作为布尔值来标记应该突出显示哪些选项卡。

tabItem.Tag = true;

正如 Arie 所说，我需要在我的 XAML 文件中覆盖 TabItem 的模板。我使用this method生成了TabItem的默认模板。

最后一步是在触发器中定义一些 Setter 来检查 Tag 属性是否设置为 true。此外，您需要定义 Tag 应转换为布尔值而不是字符串。为此，您需要在 Window 元素中定义 sys：

<Window ...
    xmlns:sys="clr-namespace:System;assembly=mscorlib"
... >

将属性 Tag 解释为布尔值：

<Trigger.Value>
    <sys:Boolean>True</sys:Boolean>
</Trigger.Value>

生成的TabItem 模板：

<TabControl ... >
    <TabControl.Resources>
        <Style TargetType="TabItem">
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="TabItem">
                        <Grid SnapsToDevicePixels="True">
                            <Border x:Name="Bd" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="1,1,1,0" Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}">
                                <ContentPresenter x:Name="Content" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" ContentStringFormat="{TemplateBinding HeaderStringFormat}" ContentSource="Header" HorizontalAlignment="{Binding HorizontalContentAlignment, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ItemsControl}}}" RecognizesAccessKey="True" SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" VerticalAlignment="{Binding VerticalContentAlignment, RelativeSource={RelativeSource FindAncestor, AncestorLevel=1, AncestorType={x:Type ItemsControl}}}"/>
                            </Border>
                        </Grid>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Setter Property="Background" TargetName="Bd">
                                    <Setter.Value>
                                        <LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
                                            <GradientStop Color="#FFEAF6FD" Offset="0.15"/>
                                            <GradientStop Color="#FFD9F0FC" Offset="0.5"/>
                                            <GradientStop Color="#FFBEE6FD" Offset="0.5"/>
                                            <GradientStop Color="#FFA7D9F5" Offset="1"/>
                                        </LinearGradientBrush>
                                    </Setter.Value>
                                </Setter>
                            </Trigger>
                            <Trigger Property="Tag">
                                <Trigger.Value>
                                    <sys:Boolean>True</sys:Boolean>
                                </Trigger.Value>
                                <Setter Property="Background" TargetName="Bd">
                                    <Setter.Value>
                                        <LinearGradientBrush EndPoint="0,1" StartPoint="0,0">
                                            <GradientStop Color="#FFFFEAC7" Offset="0.15"/>
                                            <GradientStop Color="#FFFFE9C2" Offset="0.5"/>
                                            <GradientStop Color="#FFFFE1AD" Offset="0.5"/>
                                            <GradientStop Color="#FFFFDDA3" Offset="1"/>
                                        </LinearGradientBrush>
                                    </Setter.Value>
                                </Setter>
                            </Trigger>
                            <Trigger Property="IsSelected" Value="True">
                                <Setter Property="Panel.ZIndex" Value="1"/>
                                <Setter Property="Background" TargetName="Bd" Value="#FFF9F9F9"/>
                            </Trigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="True"/>
                                    <Condition Property="Tag">
                                        <Condition.Value>
                                            <sys:Boolean>True</sys:Boolean>
                                        </Condition.Value>
                                    </Condition>
                                </MultiTrigger.Conditions>
                                <Setter Property="Background" TargetName="Bd" Value="#FFFFE5C1"/>
                            </MultiTrigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="False"/>
                                    <Condition Property="IsMouseOver" Value="True"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="BorderBrush" TargetName="Bd" Value="#FF3C7FB1"/>
                            </MultiTrigger>
                            <Trigger Property="TabStripPlacement" Value="Bottom">
                                <Setter Property="BorderThickness" TargetName="Bd" Value="1,0,1,1"/>
                            </Trigger>
                            <Trigger Property="TabStripPlacement" Value="Left">
                                <Setter Property="BorderThickness" TargetName="Bd" Value="1,1,0,1"/>
                            </Trigger>
                            <Trigger Property="TabStripPlacement" Value="Right">
                                <Setter Property="BorderThickness" TargetName="Bd" Value="0,1,1,1"/>
                            </Trigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="True"/>
                                    <Condition Property="TabStripPlacement" Value="Top"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="Margin" Value="-2,-2,-2,-1"/>
                                <Setter Property="Margin" TargetName="Content" Value="0,0,0,1"/>
                            </MultiTrigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="True"/>
                                    <Condition Property="TabStripPlacement" Value="Bottom"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="Margin" Value="-2,-1,-2,-2"/>
                                <Setter Property="Margin" TargetName="Content" Value="0,1,0,0"/>
                            </MultiTrigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="True"/>
                                    <Condition Property="TabStripPlacement" Value="Left"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="Margin" Value="-2,-2,-1,-2"/>
                                <Setter Property="Margin" TargetName="Content" Value="0,0,1,0"/>
                            </MultiTrigger>
                            <MultiTrigger>
                                <MultiTrigger.Conditions>
                                    <Condition Property="IsSelected" Value="True"/>
                                    <Condition Property="TabStripPlacement" Value="Right"/>
                                </MultiTrigger.Conditions>
                                <Setter Property="Margin" Value="-1,-2,-2,-2"/>
                                <Setter Property="Margin" TargetName="Content" Value="1,0,0,0"/>
                            </MultiTrigger>
                            <Trigger Property="IsEnabled" Value="False">
                                <Setter Property="Background" TargetName="Bd" Value="#FFF4F4F4"/>
                                <Setter Property="BorderBrush" TargetName="Bd" Value="#FFC9C7BA"/>
                                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </TabControl.Resources>
    <TabItem></TabItem>
</TabControl>