使对象跟随另一个对象

Question

我正在尝试创建某种窗口或工具箱，它可以被其标题部分拖动，就像任何窗口一样。出于某种原因，它似乎对我不起作用。标题移动但身体部位保持不动。

这是我的代码：

    BehaviorCollection behaviorCollection = Interaction.GetBehaviors(this._explorerHeader);
    MouseDragElementBehavior mouseDragBehavior = new MouseDragElementBehavior { ConstrainToParentBounds = false };
    mouseDragBehavior.Dragging += (s1, e1) =>
    {
        Canvas.SetLeft(this._explorerBody, (Double)_explorerHeader.GetValue(Canvas.LeftProperty));
        Canvas.SetTop(this._explorerBody, ((Double)_explorerHeader.GetValue(Canvas.TopProperty) + _explorerHeader.ActualHeight));                        
    };
    behaviorCollection.Add(mouseDragBehavior); 

更新

这是控件的控件模板：

    <Style x:Key="ApplicationExplorerDefaultStyle" TargetType="Controls:ApplicationExplorer">
        <Setter Property="Width" Value="150" />
        <Setter Property="Height" Value="300" />
        <Setter Property="CornerRadius" Value="0" />
        <Setter Property="Background" Value="{StaticResource LightBlue}" />
        <Setter Property="HeaderBackgroundBrush" Value="{StaticResource VeryLightBlue}" />
        <Setter Property="BorderThickness" Value="0" />
        <Setter Property="BorderBrush" Value="Black" />
        <Setter Property="TreeItemTemplate" Value="{StaticResource ChildTemplate}" />
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="Controls:ApplicationExplorer">                        
                    <Border BorderBrush="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=BorderBrush}" 
                            BorderThickness="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=BorderThickness}" 
                            CornerRadius="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=CornerRadius}" 
                            Width="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Width}" 
                            Height="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Height}" >

                        <Grid x:Name="Root" MinWidth="100">
                            <Grid.RowDefinitions>
                                <RowDefinition Height="30" />
                                <RowDefinition Height="*" />
                            </Grid.RowDefinitions>
                            <Grid x:Name="ExplorerHeader" Grid.Row="0" Background="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=HeaderBackgroundBrush}">
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="10" />
                                    <ColumnDefinition Width="*" />
                                    <ColumnDefinition Width="40" />
                                </Grid.ColumnDefinitions>
                                <TextBlock Grid.Column="1" Text="{TemplateBinding Title}" Style="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TitleStyle}" VerticalAlignment="Center" />
                                <Controls:LayoutToggleButton Grid.Column="2" x:Name="LayoutButton" Cursor="Hand" />
                            </Grid>
                            <Border x:Name="ExplorerBody" Background="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=Background}" 
                                    Grid.Row="1" HorizontalAlignment="Stretch" BorderThickness="0" >
                                <toolkit:TreeViewDragDropTarget AllowedSourceEffects="Copy" x:Name="treeViewDropTarget" 
                                                        HorizontalAlignment="Left" VerticalAlignment="Top" >
                                    <sdk:TreeView x:Name="treeView" ItemsSource="{TemplateBinding Nodes}" Background="Transparent" BorderThickness="0"
                                        ItemTemplate="{Binding RelativeSource={RelativeSource TemplatedParent}, Path=TreeItemTemplate}" 
                                        HorizontalAlignment="Left" Margin="10 0 0 0" />
                                </toolkit:TreeViewDragDropTarget>
                           </Border>
                        </Grid>
                    </Border>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

有什么建议吗？