第二次绑定到PointCollection未被渲染 [英] 2nd time binding to PointCollection not being rendered

问题描述

我有一个ItemsControl的ItemsSource（通过代码）将INotifyPropertyChanged对象（数据模型）的ObservableCollection（让它称为Items）。该数据模型具有PointCollection属性。

视图（XAML）绑定到PolyLine上的PointCollection（在Points属性上）。
最初当我将此Items集合设置到ItemsControl.ItemsSource时，我可以看到这些行确实呈现。

问题：
当我将ItemsControl.ItemsSource设置为其他东西（如另一个没有任何行的ObservableCollection），那么将其设置回原始集合，即使集合SHOULD呈现，我无法看到这些行他们因为收集数据模型包含PointCollection。

从我能够研究的内容中，对于绑定到PointCollection有一些特别的困难。我想知道有没有人在之前和/或知道一个方法来解决这个问题（即无效控制以某种方式强制重画）？

谢谢。

解决方案

Alvin，

我不知道如果将工作，但是您是否尝试创建一个新的PointCollection？：

  PointCollection newCollection = new PointCollection（oldCollection）; 
 myItemsControl.ItemsSource = newCollection; 
  

如果这不起作用，也许可能需要使用更多基于WPF的语法： p>

  myItemsControl.SetValue（ItemsControl.PointsProperty，newCollection）; 
  

我自己遇到了一些PointCollection问题，所以如果这些选项之一有帮助，让我知道。 / p>

I have an ItemsControl whose ItemsSource I assign (via code) an ObservableCollection (lets call it Items) of INotifyPropertyChanged objects (data model). This data model has a PointCollection property.

The view (XAML) binds to this PointCollection on a PolyLine (on the Points attribute). Initially when i set this Items collection to the ItemsControl.ItemsSource, i can see that the lines are indeed rendered.

Issue: When I set the ItemsControl.ItemsSource to something else (like another ObservableCollection which doesn't have any lines) THEN set it back to the original collection, I am unable to see the lines, even though the collection SHOULD render them because the collection data model's contain the PointCollection.

From what I was able to research, there is something particularly tricky about binding to a PointCollection. I was wondering if anybody has tackled this before and/or know of a way to get this to render (i.e. invalidate the control to somehow force a redraw)???

Thanks.

解决方案

Alvin,

I have no idea if this will work but, have you tried creating a new PointCollection?:

PointCollection newCollection = new PointCollection( oldCollection );
myItemsControl.ItemsSource = newCollection;

If that doesn't work, maybe it may be necessary use a more WPF based syntax:

myItemsControl.SetValue( ItemsControl.PointsProperty, newCollection );

I am struggling with some PointCollection issues myself so if either of these options help, let me know.

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