如何检查具有特定属性的对象的List集合？

Question

I have a List<IAgStkObject> . Each IAgStkObject has a property called InstanceName . How can I search through my List to find if any of the contained IAgStkObject(s) have a particular InstanceName? In the past I would have used a foreach loop.. but this seems too slow.

WulfgarPro

Answer 1

If the only thing you have is a List (not ordered by InstanceName), there is no faster way (if you do similar tests often, you can preprocess the data and create eg a Dictionary indexed by the InstanceName).

The only way different from “the past” would be those useful extension methods allowing you to write just

return myList.Any(item => item.InstanceName == "Searched name");

Answer 2

If the list is sorted by the InstanceName, you can use binary search algorithm, otherwise: no.

You would have to use some more advanced data structure (like the sorted list or dictionary). I think dictionary would be the solution for this. It is very fast and easy to use.

But think: how many of the objects do you have ? Are you sure looping through them is performance issue? If you have < 1000 of the objects, you absolutely don't have to worry (unless you want to do something in real time).

Answer 3

You can use Linq :

list.Any(o => o.InstanceName == "something")

But you cannot avoid looping through the list (in the Linq case it's done implicitly). If you want a performance gain, change your data structure. Maybe a dictionary (InstanceName -> IAgStkObject ) is appropriate?