在画布周围移动ListBoxItem?

我正致力于在画布周围拖动对象,画布封装在ListBoxItems中——其效果是创建一个简单的伪桌面。

我有一个列表框,其中画布作为itemspaneltempalte,以便列表框项可以显示在屏幕上的任何位置:

<ListBox ItemsSource="{Binding Windows}">
    <ListBox.ItemsPanel>
        <ItemsPanelTemplate>
            <Canvas />
        </ItemsPanelTemplate>
    </ListBox.ItemsPanel>
</ListBox>

我有一个样式来定义ListBoxItem的显示方式:

<Style TargetType="{x:Type ListBoxItem}">
    <Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
    <Setter Property="Canvas.Left" Value="{Binding Left, Mode=TwoWay}" />
    <Setter Property="Canvas.Top" Value="{Binding Top, Mode=TwoWay}" />
    <Setter Property="OverridesDefaultStyle" Value="True" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ListBoxItem}">
                <local:PseudoWindowContainer Content="{TemplateBinding Content}" />
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

“伪窗口容器”从ContentControl扩展而来,并应用了自己的样式,使其看起来像一个对话框(标题栏、关闭按钮等)。这里有一大块:

  <Style TargetType="{x:Type local:PseudoWindowContainer}">
<Setter Property="IsSelected" Value="{Binding IsSelected, Mode=TwoWay}" />
<Setter Property="Width" Value="{Binding Width, Mode=TwoWay}" />
<Setter Property="Height" Value="{Binding Height, Mode=TwoWay}" />
<Setter Property="OverridesDefaultStyle" Value="True" />
<Setter Property="Template">
  <Setter.Value>
    <ControlTemplate TargetType="{x:Type local:PseudoWindowContainer}">
      <Grid Name="LayoutRoot" Background="White">
        <!-- ... snip ... -->
            <Border Name="PART_TitleBar" Grid.Row="0" Background="LightGray" CornerRadius="2,2,0,0" VerticalAlignment="Stretch" Cursor="Hand" />
            <TextBlock Name="TitleBar_Caption" Text="{Binding DisplayName}" Grid.Row="0" Background="Transparent" Padding="5,0,0,0" HorizontalAlignment="Left" VerticalAlignment="Center" />
            <Button Name="TitleBar_CloseButton" Command="{Binding CloseCommand}" Grid.Row="0" VerticalAlignment="Top" HorizontalAlignment="Right" Margin="0,5,5,0" Width="20" Height="20" Cursor="Hand" Background="#FFFF0000" Foreground="#FF212121" />
            <!-- ContentPresenter -->
            <ContentPresenter Grid.Row="1" />
        <!-- ... snip ... -->
      </Grid>
      <ControlTemplate.Triggers>
        <Trigger Property="IsSelected" Value="True">
          <Setter TargetName="WindowBorder" Property="Background" Value="Blue" />
        </Trigger>
        <Trigger Property="IsSelected" Value="False">
          <Setter TargetName="WindowBorder" Property="Background" Value="#22000000" />
        </Trigger>
      </ControlTemplate.Triggers>
    </ControlTemplate>
  </Setter.Value>
</Setter>

在pseudowindowcontainer.cs类中,我创建一些事件处理程序来侦听mousedown/mouseup/movemove事件:

public override void OnApplyTemplate()
{
  _titleBar = (Border)Template.FindName("PART_TitleBar", this);
  if (_titleBar != null)
  {
    _titleBar.MouseDown += TitleBar_MouseDown;
    _titleBar.MouseUp += TitleBar_MouseUp;
  }

  _grip = (ResizeGrip)Template.FindName("PART_ResizeGrip", this);
  if (_grip != null)
  {
    _grip.MouseLeftButtonDown += ResizeGrip_MouseLeftButtonDown;
    _grip.MouseLeftButtonUp += ResizeGrip_MouseLeftButtonUp;
  }

  base.OnApplyTemplate();
}

private void TitleBar_MouseDown(object sender, MouseButtonEventArgs e)
{
  _titleBar.MouseMove += TitleBar_MouseMove;
  ((Border)sender).CaptureMouse();

  _windowLocation.X = Left;
  _windowLocation.Y = Top;

  _clickLocation = this.PointToScreen(Mouse.GetPosition(this));
}

private void TitleBar_MouseUp(object sender, MouseButtonEventArgs e)
{
  _titleBar.MouseMove -= TitleBar_MouseMove;
  ((Border)sender).ReleaseMouseCapture();
}

private void TitleBar_MouseMove(object sender, MouseEventArgs e)
{
  Point currentLocation = this.PointToScreen(Mouse.GetPosition(this));

  Left = _windowLocation.X + currentLocation.X - _clickLocation.X;
  Top = _windowLocation.Y + currentLocation.Y - _clickLocation.Y;
}

我遇到的问题是“左”和“上”没有定义属性,并且更新到canvas.setleft/settop(或getleft/gettop,相应地)不会更新canvas上的位置。

我在所放置控件的视图模型中定义了“左”和“上” 进入之内 然后,由于模板的原因,用一个伪窗口容器包装ListBoxItem和。当应用程序最初出现时,这些值会得到尊重,对象会出现在正确的位置。

我相信我需要在我的伪窗口容器(又称:ContentControl)中定义“左”和“上”,并让它们传播回我的视图模型。这有可能吗?

再次感谢您的帮助!