wpf 从嵌套 Foreach 中的 Observable 集合中删除项目
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Remove item from Observable Collection in Nested Foreach
提问by Abdulsalam Elsharif
I have these nested Foreach :
我有这些嵌套的 Foreach ：
foreach (var item1 in ocChoicesinItem)
{
foreach (var item2 in temp.ItemsInInvoiceChoices)
{
if (item1.ChoicesId == item2.ChoicesId)
ocChoicesinItem.Remove(item1);
}
}
The problem occur when remove item from ocChoicesinItem, gives me this error:
从 ocChoicesinItem 中删除项目时出现问题，给我这个错误：
Is there any way to accomplish this?
有什么办法可以做到这一点吗？
Thanks in advance.
提前致谢。
回答by Seb
You need to add 'ToList' statements if you want to remove items in the collection :
如果要删除集合中的项目，则需要添加“ToList”语句：
foreach (var item1 in ocChoicesinItem.ToList())
{
foreach (var item2 in temp.ItemsInInvoiceChoices)
{
if (item1.ChoicesId == item2.ChoicesId)
ocChoicesinItem.Remove(item1);
}
}
回答by Yuval Itzchakov
You can't modify a collection while iterating that collection, as you are making your Enumeratorinvalid when calling MoveNext
您不能在迭代该集合时修改该集合，因为您Enumerator在调用时使您的无效MoveNext
Try:
尝试：
public static class ExtensionMethods
{
public static int RemoveAll<T>(
this ObservableCollection<T> coll, Func<T, bool> condition)
{
var itemsToRemove = coll.Where(condition).ToList();
foreach (var itemToRemove in itemsToRemove)
{
coll.Remove(itemToRemove);
}
return itemsToRemove.Count;
}
}
ocChoicesinItem.RemoveAll(x => temp.ItemsInInvoiceChoices.Any(y => y.ChoicesId == x.ChoicesId);
回答by Jay
Try something like
尝试类似
List<string> ocChoicesinItem = new List<string>{"One", "Two", "Three"};
List<string> ItemsInInvoiceChoices = new List<string> { "Three" };
ocChoicesinItem.RemoveAll(x => ItemsInInvoiceChoices.Contains(x));
Obviously I am using strings as I don't know what type your collections contain; you may have to compare the ID's in the predicate.
显然我使用的是字符串，因为我不知道您的集合包含什么类型；您可能需要比较谓词中的 ID。
