22 to 0.3 seconds!
I found a simple solution to a very common problem. While profiling I found that remove in this little method took a lot of the time.
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public void MovePropertyFirst(IProperty property) { properties.Remove(property); properties.Insert(0, property); } |
The reason was, that it’s time consuming to compare the properties by equality, for complex types. I think that in most (?) cases we want to delete the very same instance we supply as parameter to the remove method.
So I implemented a ReferenceEquals based remove, and by that I cut the time spent in remove by about 72 times!
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public static bool RemoveFrom<T>(this IList<T> list, T itemToRemove) { if(list.Count == 0) return false; int index = 0; foreach (var item in list) { if (ReferenceEquals(item, itemToRemove)) { list.RemoveAt(index); return true; } index++; } Debug.Assert(false, "Item to delete not found"); //equality based fall back return list.Remove(itemToRemove); } |
Mattias
5 Mar 2010Could you explain the ReferenceEqual method please?
bjorncarlsson
5 Mar 2010It’s like comparing pointers. Checks that it’s the same instance.