CODEWITHSUNDEEP
c#silverlight-4.0
TCM
TCM

Reputation: 16900

How can I sort ObservableCollection<T> such that my UI also sees the process of sorting?

I have Listbox whose item panel is set to wrappanel. I want that whenever a new item is added to listbox my collection should be sorted and the process should be visible on the UI. I mean the user should be able to see that fancy effect to help them identify that the item is being sorted. I looked at few posts on stackoverflow and they suggest to use CollectionViewSource. However my itemsource is bound to ObservableCollection in ViewModel.

First I wrote this code. It works however as a new collection is bound I can't see that fancy effect where the items in the container just move to their new position from the original position :-

 var photoList = PhotosToUpload.ToList<Photo>();
            photoList.Sort(new PhotoSorter());
            PhotosToUpload = new ObservableCollection<Photo>(photoList);

This is my class :-

 public class PhotoSorter : IComparer<Photo>
    {

        public int Compare(Photo x, Photo y)
        {
            return x.PhotoByteArr.Length - x.PhotoByteArr.Length;
        }
    }

Then I wrote a simple bubble sorting algorithm. This achives the desired effect but I don't know why it takes too long time. I know it's the most ineffecient algorithm that anybody can think of but still sorting 10 items shouldn't take more than a second. Here it takes 4-5 seconds.

for (int i = 0; i < PhotosToUpload.Count; i++)
            {
                for (int j = 0; j < PhotosToUpload.Count - 1 - i; j++)
                {
                    if (PhotosToUpload[j].PhotoByteArr.Length > PhotosToUpload[j + 1].PhotoByteArr.Length)
                    {
                        Photo photo = PhotosToUpload[j];
                        PhotosToUpload[j] = PhotosToUpload[j + 1];
                        PhotosToUpload[j + 1] = photo;
                    }
                }
            }

Can anybody tell me what's the best I can do at this point of time? and why is bubble sorting taking so long even with just 10 items?

Upvotes: 3

Views: 336

Answers (1)

Amy West
Amy West

Reputation: 163

To check for changes, use the CollectionChanged event.

You have an error in your comparer:

return x.PhotoByteArr.Length - y.PhotoByteArr.Length;

btw. your code executes instantly for me... Maybe the problem is in your Photo class? Or your binding/events?

Is Photo.PhotoByteArr a calculated value?

Upvotes: 1

Related Questions