Question

我一直致力于MVVM风格应用程序中的小型3D预览窗口...创建视图然后设置其数据上下文。因此，似乎ZoomExtentsWhenLoaded =“True”似乎没有帮助做我需要的。我需要像ZoomExtentsWhenDataContextChanges这样的东西。

有趣的是，我发现如果我使用类似下面定义的鼠标手势，我可以在物理上点击HelixViewport3D，它将执行ZoomExtents。

HelixViewport3D.ZoomExtentsGesture = new MouseGesture(MouseAction.LeftDoubleClick);

但是，如果做这样的事情......

HelixViewport3D.DataContextChanged += (o, e) => ResetCamera();

private void ResetCamera()
{
    var dc = HelixViewport3D.DataContext as WellSurveyPlot3DViewModel;
    HelixViewport3D.ResetCamera();
    HelixViewport3D.Camera = dc.PerspectiveCamera;
    HelixViewport3D.ZoomExtents();
}

视口会进行缩放，它不会居中，就像使用鼠标手势时激活ZoomExtents时一样。

我尝试过ResetCamera以及其他一些事情......处理保持视口并交换DataContext而不是每次都创建一个新视图的标准方法是什么？

Answer 1

我用附加属性修复了这个问题。我仔细阅读了HelixViewport3D源代码，并在注意到相机如何工作后得到了这个想法。在初始化控件之后，似乎通过属性绑定更新默认摄像头并没有真正做任何事情。

  public static class HelixViewport3DZoomExtent
{
    private static readonly Type OwnerType = typeof(HelixViewport3DZoomExtent);
    public static readonly DependencyProperty ZoomExtentsOnUpdateProperty = DependencyProperty.RegisterAttached("ZoomExtentsOnUpdate", typeof(bool), OwnerType, new PropertyMetadata(false, OnDataContextChanged));

    public static bool GetZoomExtentsOnUpdate(DependencyObject obj)
    {
        return (bool)obj.GetValue(ZoomExtentsOnUpdateProperty);
    }
    public static void SetZoomExtentsOnUpdate(DependencyObject obj, bool value)
    {
        obj.SetValue(ZoomExtentsOnUpdateProperty, value);
    }
    private static void OnDataContextChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var viewport = d as HelixViewport3D;
        if (viewport == null) return;
        if (viewport.DataContext == null) return;
        viewport.Camera = viewport.DefaultCamera;
        viewport.ZoomExtents();
    }
}

这是Xaml

 <Border BorderBrush="Black" BorderThickness="1">

    <Grid>

        <h:HelixViewport3D Name="HelixViewport3D" 
                           PanGesture="LeftClick"
                           DataContext="{Binding PreviewPlot, UpdateSourceTrigger=PropertyChanged}"
                           DefaultCamera="{Binding PerspectiveCamera, UpdateSourceTrigger=PropertyChanged}" 
                           services:HelixViewport3DZoomExtent.ZoomExtentsOnUpdate="{Binding RelativeSource={RelativeSource AncestorType={x:Type views:WellSurveyPlot3DPreview}}, 
                                                                                    Path=DataContext.PreviewUpdatedReZoom, UpdateSourceTrigger=PropertyChanged}">

            <h:SunLight/>

            <h:TubeVisual3D  Path="{Binding TubePath}" Diameter="75" ThetaDiv="12" IsPathClosed="False" Fill="LightGray"/>

            <h:GridLinesVisual3D Width="{Binding GridLength}" Length="{Binding GridLength}" MajorDistance="{Binding MajorGridLines}" Thickness="25"
                             MinorDistance="{Binding MajorGridLines, UpdateSourceTrigger=PropertyChanged}" LengthDirection="1,0,0" Normal="0,0,1" 
                             Center="{Binding BottomPlaneCenter,UpdateSourceTrigger=PropertyChanged}" Fill="Red"   />
            <h:GridLinesVisual3D Width="{Binding GridLength}" Length="{Binding GridLength, UpdateSourceTrigger=PropertyChanged}" LengthDirection="0,0,1" Normal="1,0,0"  Thickness="25"
                             MajorDistance="{Binding MajorGridLines}" MinorDistance="{Binding MajorGridLines}"
                             Center="{Binding BackLeftPlaneCenter, UpdateSourceTrigger=PropertyChanged}" Fill="Blue" />
            <h:GridLinesVisual3D Width="{Binding GridLength}" Length="{Binding GridLength, UpdateSourceTrigger=PropertyChanged}" LengthDirection="1,0,0" Normal="0,1,0" Thickness="25"
                             MajorDistance="{Binding MajorGridLines}" MinorDistance="{Binding MajorGridLines}" 
                             Center="{Binding BackRightPlaneCenter,UpdateSourceTrigger=PropertyChanged}" Fill="Green" />

        </h:HelixViewport3D>

        <Button Content="Open Well Viewer" HorizontalAlignment="Left"  VerticalAlignment="Top" Command="{Binding OpenWindowCmd}"/>

    </Grid>
</Border>

在我的视图模型中，我必须切换我的PreviewUpdateReZoom属性。

private void LoadSurveyPoints(List<WellSurveyPointCalculated> surveyPoints)
    {
        _coordinatesCalculator = _calcGlobalCoordsFactory.Create(surveyPoints);
        _wellXyzCoordinates = _coordinatesCalculator.PlotGlobalCoordinates(100).ToList();
        PreviewPlot = WellSurveyPlot3DViewModel();
        PreviewUpdatedReZoom = false;//Toggle true false to send property changed and get attached property to fire.
        PreviewUpdatedReZoom = true;
    }

现在这样可以使绘制到视口中的每个新项目都具有正确的相机设置并缩放到范围...

Helix 3D Toolkit - ZoomExtents方法调用与通过手势激活ZoomExtents不同

1 个答案: