Question

我在C＃中创建了一个故事板，用于在画布上动画缩放变换。比例变换是布局变换。这是动画的C＃代码：

Storyboard Configuring = new Storyboard();
if (NexusRoot != null)
{
var current = (NexusRoot.LayoutTransform as ScaleTransform).ScaleX;

Duration duration = new Duration(TimeSpan.FromSeconds(1));

DoubleAnimation myDoubleAnimation1 = new DoubleAnimation();
myDoubleAnimation1.Duration = duration;
Configuring.Children.Add(myDoubleAnimation1);
myDoubleAnimation1.From = current;
myDoubleAnimation1.To = scale;
Storyboard.SetTarget(myDoubleAnimation1, NexusRoot);
Storyboard.SetTargetProperty(myDoubleAnimation1, (PropertyPath)new PropertyPathConverter().ConvertFromString("(UIElement.LayoutTransform).(ScaleTransform.ScaleX)"));

DoubleAnimation myDoubleAnimation2 = new DoubleAnimation();
myDoubleAnimation2.Duration = duration;
Configuring.Children.Add(myDoubleAnimation2);
myDoubleAnimation2.From = current;
myDoubleAnimation2.To = scale;

Storyboard.SetTargetName(myDoubleAnimation2, "NexusRoot");
Storyboard.SetTargetProperty(myDoubleAnimation2, (PropertyPath)new PropertyPathConverter().ConvertFromString("(UIElement.LayoutTransform).(ScaleTransform.ScaleY)"));
}

当我运行此动画时，它会抛出以下异常。

System.ArgumentNullException是   抓住消息=“价值不可能   null。\ r \ n参数名称：dp“
  Source =“WindowsBase”ParamName =“dp”   堆栈跟踪：          在System.Windows.DependencyObject.GetValue（DependencyProperty   DP）          在System.Windows.Media.Animation.Storyboard.ProcessComplexPath（HybridDictionary   clockMappings，DependencyObject   targetObject，PropertyPath路径，   AnimationClock animationClock，   HandoffBehavior handoff行为，Int64   层）          在System.Windows.Media.Animation.Storyboard.ClockTreeWalkRecursive（时钟   currentClock，DependencyObject   containsObject，INameScope   nameScope，DependencyObject   parentObject，String parentObjectName，   PropertyPath parentPropertyPath，   HandoffBehavior handoff行为，   HybridDictionary clockMappings，Int64   层）          在System.Windows.Media.Animation.Storyboard.ClockTreeWalkRecursive（时钟   currentClock，DependencyObject   containsObject，INameScope   nameScope，DependencyObject   parentObject，String parentObjectName，   PropertyPath parentPropertyPath，   HandoffBehavior handoff行为，   HybridDictionary clockMappings，Int64   层）          在System.Windows.Media.Animation.Storyboard.BeginCommon（DependencyObject   containsObject，INameScope   nameScope，HandoffBehavior   handoffBehavior，布尔   isControllable，Int64层）          在System.Windows.Media.Animation.Storyboard.Begin（）          在StormFront.NexusDesigner.ScaleCanvasAnimation（Double   C：\ Documents和   设置\ lbeaver \桌面\ StormFront \ WPF \ StormFront \ StormFront \ NexusDesigner.xaml.cs：行   544 InnerException：

如何阻止此异常发生？

Answer 1

我发现了我的问题。问题出在属性路径上。我正在使用UIElement，应该使用FrameworkElement。

所以这一行：

Storyboard.SetTargetProperty(myDoubleAnimation1, (PropertyPath)new PropertyPathConverter().ConvertFromString("(UIElement.LayoutTransform).(ScaleTransform.ScaleX)"));

应该是：

Storyboard.SetTargetProperty(myDoubleAnimation1, (PropertyPath)new PropertyPathConverter().ConvertFromString("(FrameworkElement.LayoutTransform).(ScaleTransform.ScaleX)"));

在WPF中为缩放布局转换设置动画的异常

1 个答案: