Question

我的每个var database = require('../Code/Database/Database'); var expect = require('chai').expect; //Tests for the Database class. describe("#Database", function(){ //Test for the makeConnection method describe("#makeConnection", function(){ it("should make a connection with the database", function(){ expect(database.isConnected).to.be.false; var connection = database.makeConnection(); expect(database.isConnected).to.be.true; }) }) })都有一个TabControl和一种风格（TabItem）。我希望每个StyleSelector在所选项目更改时更改其样式。

所以我创建了一个TabItem，其中包含一个属性TabItemCustom：

IsItemAfterSelected

如果选择了下一个项目之一，则此属性必须包含public class TabItemCustom: TabItem { public static readonly DependencyProperty IsItemAfterSelectedProperty = DependencyProperty.Register("IsItemAfterSelected", typeof(bool), typeof(TabItemCustom), new PropertyMetadata(false)); public bool IsItemAfterSelected { get { return (bool)GetValue(IsItemAfterSelectedProperty ); } set { SetValue(IsItemAfterSelectedProperty , value); } } }。

我可以知道True的更改时间SelectedIndex：

DataTrigger

我使用相同的转换器来检测<sys:Boolean x:Key="StyleValueTrue">True</sys:Boolean> <DataTrigger Binding="{Binding Path=SelectedIndex, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type TabControl}}, Mode=TwoWay, Converter={StaticResource ConverterTabItemAriane}}" Value="{StaticResource StyleValueTrue}"> <Setter Property="IsItemAfterSelected" Value="{Binding Converter={StaticResource ConverterTabItemAriane}, RelativeSource={RelativeSource Self}}"/> </DataTrigger>是否（如果整数总是返回SelectedIndex）并设置我的值：

True

我已经检查过断点：当我更改所选项目时，它进入转换器并返回public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { if (value is DependencyObject) { DependencyObject container = (DependencyObject)value; var itemsControl = ItemsControl.ItemsControlFromItemContainer(container); var itemIndex = itemsControl.ItemContainerGenerator.IndexFromContainer(container); if (itemsControl is TabControl) { TabControl tabcontrol = (TabControl)itemsControl; if (tabcontrol.SelectedIndex >= itemIndex) return true; else return false; } } else if (value is int) return true;// selected index has changed return false; }。但是我的属性只在加载True时设置了一次。 TabControl总是返回相同的值，为什么属性设置一次？

当我能够设置此属性时，我的目标是添加Trigger，如下所示：

DataTrigger

我不知道我的方法是否最简单，但我没有找到更好的解决方案（我尝试删除<DataTrigger Property="IsItemAfterSelected" Value="True"> <Setter Property="Background" Value="Red" /> </DataTrigger>并将StyleValueTrue改为相同但结果相同）。

有什么想法解决这个问题吗？

Answer 1

如果您想使用Binding s：

进行此操作

<强> XAML：

<Style TargetType="{x:Type local:TabItemCustom}">
    <Setter Property="IsItemAfterSelected">
        <Setter.Value>
            <MultiBinding Converter="{StaticResource ConverterTabItemAriane}">
                <Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type TabControl}}"/>
                <Binding RelativeSource="{RelativeSource Self}"/>
                <Binding Path="SelectedIndex" RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type TabControl}}"/>
            </MultiBinding>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <Trigger Property="IsItemAfterSelected" Value="True">
            <Setter Property="Background" Value="Red" />
        </Trigger>
    </Style.Triggers>
</Style>

<强>转换器：

public class ConverterTabItemAriane : IMultiValueConverter
{

    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        TabControl tabControl = values[0] as TabControl;
        TabItem tabItem = values[1] as TabItem;
        if (tabControl != null && tabItem != null && values[2] is int)
        {
            var selectedIndex = (int)values[2];
            var itemIndex = tabControl.ItemContainerGenerator.IndexFromContainer(tabItem);
            return selectedIndex >= itemIndex;
        }
        return false;
    }

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }
}

如果您想在TabControl：

中进行此操作

<强> XAML：

<Style TargetType="{x:Type local:TabItemCustom}">
    <Style.Triggers>
        <Trigger Property="IsItemAfterSelected" Value="True">
            <Setter Property="Background" Value="Red" />
        </Trigger>
    </Style.Triggers>
</Style>

<强>的TabControl：

public class TabControlCustom : TabControl
{
    protected override System.Windows.DependencyObject GetContainerForItemOverride()
    {
        return new TabItemCustom();
    }

    protected override void OnSelectionChanged(SelectionChangedEventArgs e)
    {
        base.OnSelectionChanged(e);

        int i = 0;
        foreach (var item in Items)
        {
            var tabItem = ItemContainerGenerator.ContainerFromItem(item) as TabItemCustom;
            if (tabItem != null)
            {
                tabItem.IsItemAfterSelected = SelectedIndex >= i;
            }
            i++;
        }
    }
}

选定项目更改时更改tabitem样式

1 个答案: