Comments Pagination Incorrect

JSpencer

Vote:

If I have a criteria of:

            var criteria = new CompositeCriteria<CommentFilter, CommentsExtensionModel>
                           {
                               Filter = new CommentFilter { Ancestor = ancestralComment },
                               PageInfo = new PageInfo { PageSize = 2, PageOffset = 0, CalculateTotalCount = true},
                               OrderBy = { new SortInfo(CommentSortFields.Created, true) }
                           };

Call the service:

var results = _commentService.Get(criteria)

It works, no issues, 2 Results, Total Matching 5.

And as an example lets say it returns

results.Results[0].Data.Id = 123

results.Results[1].Data.Id = 456

All fine.

Now if I paginate:

            var criteria = new CompositeCriteria<CommentFilter, CommentsExtensionModel>
                           {
                               Filter = new CommentFilter { Ancestor = ancestralComment },
                               PageInfo = new PageInfo { PageSize = 2, PageOffset = 1, CalculateTotalCount = true},
                               OrderBy = { new SortInfo(CommentSortFields.Created, true) }
                           };

Again I get 2 more results, but the issue I am seeing is that:

results.Results[0].Data.Id = 456

results.Results[1].Data.Id = 789

As you can see the results returned after the pagination includes the last previous result.

Is this by design or is this a bug?

Thanks

#227538

Sep 07, 2020 12:40

Chris Banner

Vote:

Hi Jacob -- thanks for the descriptive question. This is by design. I suspect the confusion can be attributed to ambiguous naming of the property PageOffset, which could be interpreted as an index of pages rather than an index to begin the page.

The offset is a zero-based index indicating the point in the result set from which to begin returning results.

So, in your first query (Size = 2, Offset = 0), you would receive:

123	456	789	101112	131415
0	1	2	3	4

Your second query (Size = 2, Offset = 1), delivers:

123	456	789	101112	131415
0	1	2	3	4

To paginate in the manner that I imagine you're expecting, you'll want to add the page size to the previous offset to get the new one.

Size = 2, Offset = 0 (2 results)

123	456	789	101112	131415
0	1	2	3	4

Size = 2, Offset = 2 (2 results)

123	456	789	101112	131415
0	1	2	3	4

Size = 2, Offset = 4 (1 result)

123	456	789	101112	131415
0	1	2	3	4

Hope this helps!

#227591

Edited, Sep 08, 2020 11:35

JSpencer

Vote:

Hi Chris,

Thanks for taking the time to look at my query.

The information supplied is helpful and provides insight into pagination. Definintly some confusion around PageOffset!

Thanks again

#227737

Sep 11, 2020 7:13