c# - 来自代码的 Wpf 动画

Question

有一些类似的线程，但我没有找到解决问题的方法。这是我在这里的第一篇文章。
事情是这样的:

Viewport3D viewPort3D;

GeometryModel3D geometryModel = new GeometryModel3D();  
Transform3DGroup transform3DGroup = new Transform3DGroup();

...

// Rotation
RotateTransform3D rotateTransform3D = new RotateTransform3D();   
AxisAngleRotation3D axisAngleRotation3d = new AxisAngleRotation3D();  
axisAngleRotation3d.Axis = new Vector3D(0, 1, 0);  
axisAngleRotation3d.Angle = angle;  
rotateTransform3D.Rotation = axisAngleRotation3d;  
transform3DGroup.Children.Add(rotateTransform3D);  

// Translation  
TranslateTransform3D translateTransform3D = new TranslateTransform3D();  
translateTransform3D.OffsetX = offsetX;
transform3DGroup.Children.Add(translateTransform3D);  

// Adding transforms  
geometryModel.Transform = transform3DGroup;  

Model3DGroup model3DGroup = new Model3DGroup();
model3DGroup.Children.Add( image.getGeometryModel3D() );

modelVisual3D.Content = model3DGroup;
viewPort3D.Children.Add( modelVisual3D );

现在我想使用 Storyboard进行翻译(因为稍后我还想向该 Storyboard添加旋转):

Storyboard s = new Storyboard();

Transform3DGroup transform3DGroup = model3DGroup.Children.ElementAt(current).Transform as Transform3DGroup;

for (int j = 0; j < transform3DGroup.Children.Count; ++j)
{
   if (transform3DGroup.Children.ElementAt(j) is TranslateTransform3D)
   {
      TranslateTransform3D translation = transform3DGroup.Children.ElementAt(j) as TranslateTransform3D;

      DoubleAnimation doubleAnimation = new DoubleAnimation();
      doubleAnimation.From = 0;
      doubleAnimation.To = 2;
      doubleAnimation.Duration = new Duration(TimeSpan.FromSeconds(1));
      doubleAnimation.AutoReverse = true;
      doubleAnimation.RepeatBehavior = RepeatBehavior.Forever;

      s.Children.Add(doubleAnimation);
      s.Duration = new Duration(TimeSpan.FromSeconds(1));

      Storyboard.SetTarget(doubleAnimation, model3DGroup.Children.ElementAt(current));
      Storyboard.SetTargetProperty(doubleAnimation, new PropertyPath("(Model3D.Transform).(Transform3DGroup.Children)[1].(TranslateTransform3D.OffsetX)"));

      s.Begin(); // Exception during the execution.
   }
}

最后一行异常:

'[Unknown]' property value in the path '(Model3D.Transform).(Transform3DGroup.Children)[1].(TranslateTransform3D.OffsetX)' points to immutable instance of 'System.Windows.Media.Media3D.TranslateTransform3D'.

我取的 PropertyPath 类似于 blend 4 中生成的路径。

感谢您的帮助。

Answer 1

我认为因为 translate tranform 3d 是一个不可变的实例，所以必须指出它在进行渲染/转换时应该是可变的。

我猜

1. 我们可以向不可变的 TranslateTransform3D 对象提供 x:Name，使其可变。

2. 绑定(bind)到它的属性而不是让它动起来。

例如在你的情况下

        NameScope.SetNameScope(this, new NameScope());
        this.RegisterName("AxisRotation", MyAxisRotation3DObject.Rotation);
        this.RegisterName("TranslateTransformation", MyTranslation3DObject);

通过这种方式，我们为 Axis Rotation 3D 和 Translate Transform 3D 对象命名，然后在双动画中将它们称为 Storyboard.SetTargetName(.., "AxisRotation") 和 Storyboard.SetTargetName (.., "TranslateTransformation") 并访问它们的直接属性，例如 Storyboard.SetTargetProperty(.., new PropertyPath("Angle")) 和 Storyboard.SetTargetProperty(. ., new PropertyPath("OffsetX")) 相应的