Can't page a Datagrid using Datareader(not Dataset)

[organicg]

I'm surprised I haven't seen this posting before. Actually, there was one months ago but they decided to just bind a dataset to the datagrid, instead of a datareader. I do not want custom paging, I just want to use the provided paging functionality of the datagrid but the problem, according to the error, is that datareader does not implement ICollection. It instructs you to, well here's the error:
AllowCustomPaging must be true and VirtualItemCount must be set for 'this datagrid' when AllowPaging is set to true and the selected datasource does not implement ICollection.

Someone in the old post recommended trying to implement ICollection, but I have no idea how to do that. Does someone know how and if it can be done, or have another solution? Thanks!