C# 在 ObservableCollection 中查找索引
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Finding an index in an ObservableCollection
提问by user101010101
This may be very simple but I have not been able to come up with a solution.
这可能非常简单，但我一直无法想出解决方案。
I am have a:
我有一个：
ObservableCollection<ProcessModel> _collection = new ObservableCollection<ProcessModel>();
This collection is populated, with many ProcessModel's.
此集合已填充，其中包含许多 ProcessModel。
My question is that I have an ProcessModel, which I want to find in my _collection.
我的问题是我有一个 ProcessModel，我想在我的 _collection 中找到它。
I want to do this so I am able to find the index of where the ProcessModel was in the _collection, I am really unsure how to do this.
我想这样做，所以我能够找到 ProcessModel 在 _collection 中的位置的索引，我真的不确定如何做到这一点。
I want to do this because I want to get at the ProcessModel N+1 ahead of it in the ObservableCollection (_collection).
我想这样做是因为我想在 ObservableCollection (_collection) 中提前获得 ProcessModel N+1。
采纳答案by daryal
var x = _collection[(_collection.IndexOf(ProcessItem) + 1)];
回答by Kendall Frey
http://msdn.microsoft.com/en-us/library/ms132410.aspx
http://msdn.microsoft.com/en-us/library/ms132410.aspx
Use:
用：
_collection.IndexOf(_item)
Here is some code to get the next item:
这是获取下一个项目的一些代码：
int nextIndex = _collection.IndexOf(_item) + 1;
if (nextIndex == 0)
{
// not found, you may want to handle this as a special case.
}
else if (nextIndex < _collection.Count)
{
_next = _collection[nextIndex];
}
else
{
// that was the last one
}
回答by Nikhil Agrawal
Since ObservableCollectionis a sequence, hence we can use LINQ
由于ObservableCollection是一个序列，因此我们可以使用LINQ
int index =
_collection.Select((x,i) => object.Equals(x, mydesiredProcessModel)? i + 1 : -1)
.Where(x => x != -1).FirstOrDefault();
ProcessModel pm = _collection.ElementAt(index);
I already incremented your index to 1 where it matches your requirement.
我已经将您的索引增加到 1，它符合您的要求。
OR
或者
ProcessModel pm = _collection[_collection.IndexOf(mydesiredProcessModel) + 1];
OR
或者
ProcessModel pm = _collection.ElementAt(_collection.IndexOf(mydesiredProcessModel) + 1);
EDIT for Not Null
编辑不为空
int i = _collection.IndexOf(ProcessItem) + 1;
var x;
if (i <= _collection.Count - 1) // Index start from 0 to LengthofCollection - 1
x = _collection[i];
else
MessageBox.Show("Item does not exist");
