筛选后的CollectionView计数错误 [英] Filtered CollectionView Gives Wrong Count

问题描述

根据文档 ，经过过滤的CollectionView的计数应仅是通过过滤器的项目数。给出以下代码：

According to the documentation, the Count of a filtered CollectionView should only be the count of items that pass the filter. Given this code:

List<string> testList = new List<string>();
testList.Add("One");
testList.Add("Two");
testList.Add("Three");
testList.Add("1-One");
testList.Add("1-Two");
testList.Add("1-Three");
CollectionView testView = new CollectionView(testList);
int testCount1 = testView.Count;
testView.Filter = (i) => i.ToString().StartsWith("1-");
int testCount2 = testView.Count;

因此，我希望testCount1为6，而testCount2为3。但是，两者均为6。如果我手动遍历CollectionView并计数项目，则得到3，但Count始终返回6。

I would therefore expect testCount1 to be 6, and testCount2 to be 3. However, both are 6. If I manually iterate through the CollectionView and count the items, I do get 3, but Count returns 6 always.

我尝试在CollectionView上调用Refresh，只是为了看看是否可以纠正结果，但是没有变化。文档是否有误？ CollectionView中有错误吗？我是在做我看不见的错吗？

I've tried calling Refresh on the CollectionView, just to see if that would correct the result, but there was no change. Is the documentation wrong? Is there a bug in CollectionView? Am I doing something wrong that I just can't see?

推荐答案

尝试

ICollectionView _cvs = CollectionViewSource.GetDefaultView(testList);

而不是

CollectionView testView = new CollectionView(testList);    

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