为什么使用IvalueConverter从ListBox拖放到另一个ListBox时文本颜色不会更改

Question

我有两个ListBox，每个都有一个TextBlock（来自DataTemplate）。我有两个按钮将文本从一个列表框传输到另一个列表框，反之亦然。

我还允许用户拖放以将文本从一个ListBox移动到另一个ListBox，这在功能上可以正常工作。

但是对于我的按钮，我使用"Style="{Binding IsInGroup, Converter={StaticResource StyleFunctionConverter}}" 当所选按钮出现在按钮上的另一个列表上时，它会改变文本样式和颜色，但是当我尝试使用拖放来传输文本时，它只是简单地传输文本而不会改变文本颜色。

我的代码：

<UserControl.Resources>
    <local:StyleFunctionConverter x:Key="StyleFunctionConverter" />
</UserControl.Resources>

<Grid x:Name="LayoutRoot" Background="{StaticResource BGBrush_1}">
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto" />
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>
    <Grid Width="200">
        <Grid.RowDefinitions>
            <RowDefinition/>
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>
        //First ListBox each ListBox inside scrollviewer
        <ScrollViewer Grid.Column="1" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" Style="{StaticResource MP_ScrollViewerStyle}" BorderBrush="{x:Null}">
            <Grid Margin="40,20">
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                    <RowDefinition Height="Auto" />
                </Grid.RowDefinitions>
                <ScrollViewer Grid.Row="1" Margin="5,5,5,5" HorizontalAlignment="Center" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" Style="{StaticResource MP_ScrollViewerStyle}" BorderBrush="{x:Null}">
                    <toolKit:ListBoxDragDropTarget AllowDrop="True" Grid.Row="1" Grid.Column="1">
                        <ListBox x:Name="GroupFunctionListBox" Width="200" Height="Auto" SelectionMode="Extended" ItemsSource="{Binding GroupFunctionList}" HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Foreground="White" Background="{StaticResource BGBrush_1}">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <TextBlock Text="{Binding Label}" Style="{Binding IsInGroup, Converter={StaticResource StyleFunctionConverter}}" />
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>
                    </toolKit:ListBoxDragDropTarget>
                </ScrollViewer>
                //These are the two buttons (=> and
                <=, the content is &lg and &gt) <Button Content="&lt;=" x:Name="AddButton" Grid.Row="1" Grid.Column="1" Height="23" HorizontalAlignment="Left" Margin="10,0,10,40" VerticalAlignment="Center" Width="75" Click="AddButton_Click" Style="{StaticResource ButtonStyle_Blue}" />
                <Button Content="=&gt;" x:Name="RemoveButton" Grid.Row="1" Grid.Column="1" Height="23" HorizontalAlignment="Left" Margin="10,80,10,0" VerticalAlignment="Center" Width="75" Click="RemoveButton_Click" Style="{StaticResource ButtonStyle_Blue}" />

                <ScrollViewer Grid.Row="1" Grid.Column="2" Margin="5,5,5,5" HorizontalAlignment="Center" ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Auto" Style="{StaticResource MP_ScrollViewerStyle}" BorderBrush="{x:Null}">
                    <toolKit:ListBoxDragDropTarget AllowDrop="True" Grid.Row="1" Grid.Column="2">
                        <ListBox x:Name="OtherFunctionListBox" Width="200" HorizontalAlignment="Center" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Disabled" Height="Auto" SelectionMode="Extended" ItemsSource="{Binding OtherFunctionList}" Foreground="White" Background="{StaticResource BGBrush_1}">
                            <ListBox.ItemTemplate>
                                <DataTemplate>
                                    <TextBlock Text="{Binding Label}" Style="{Binding IsInGroup, Converter={StaticResource StyleFunctionConverter}}" />
                                </DataTemplate>
                            </ListBox.ItemTemplate>
                        </ListBox>
                    </toolKit:ListBoxDragDropTarget>
                </ScrollViewer>

            </Grid>

我的转换器类是：（StyleFunctionConverter）

public ObservableCollection<Function> GroupFunctionList
        {
            get
            {
                return groupFunctionList;
            }
            set
            {
                groupFunctionList = value;
                NotifyPropertyChanged("GroupFunctionList");
            }
        }

        private ObservableCollection<Function> otherFunctionList;
        /// <summary>
        /// groupList
        /// </summary>
        public ObservableCollection<Function> OtherFunctionList
        {
            get
            {
                return otherFunctionList;
            }
            set
            {
                otherFunctionList = value;
                NotifyPropertyChanged("OtherFunctionList");
            }
        }

按钮点击事件是：

     private void AddButton_Click(object sender, RoutedEventArgs e)
            {
                ((GroupViewModel)this.DataContext).AddFunctionGroup((ObservableCollection<object>)OtherFunctionListBox.SelectedItems);
            }


And ViewModel Class is:

       public void AddFunctionGroup(ObservableCollection<object> selectedOtherFunction)
        {
            if (selectedOtherFunction != null)
            {
                List<Function> funcList = new List<Function>();
                foreach (object func in selectedOtherFunction)
                    funcList.Add((Function)func);
                foreach (Function func in funcList.OrderBy(c => c.Label))
                {
                    if (SelectedGroup != null && !SelectedGroup.GroupFunctionList.Contains(func))
                        func.IsInGroup = false;
                    else
                        func.IsInGroup = true;
                    GroupFunctionList.Add(func);
                    OtherFunctionList.Remove(func);
                }   
                reorderGroup();
            }
        }

        public void reorderGroup()
        {
            List<Function> TMPGroupFunctionList = new List<Function>();
            foreach (Function gfl in GroupFunctionList.OrderBy(c => c.Label))
            {
                TMPGroupFunctionList.Add(gfl);
            }
            GroupFunctionList.Clear();
            foreach (Function gfl in TMPGroupFunctionList.OrderBy(c => c.Label))
            {
                GroupFunctionList.Add(gfl);
            }

            List<Function> TMPOtherFunctionList = new List<Function>();
            foreach (Function ofl in OtherFunctionList.OrderBy(c => c.Label))
            {
                TMPOtherFunctionList.Add(ofl);
            }
            OtherFunctionList.Clear();
            foreach (Function ofl in TMPOtherFunctionList.OrderBy(c => c.Label))
            {
                OtherFunctionList.Add(ofl);
            }
        }

价值Coverter就像这样（风格）：

  public class StyleFunctionConverter : IValueConverter
            {
                public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture)
                {
                    if (value == null)
                        return null;

                    bool isInGroup = (bool)value;
                    if (isInGroup)
                        return Application.Current.Resources["ListBoxTextNormalItem"];
                    else
                        return Application.Current.Resources["ListBoxTextChangeItem"];
                }

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