Sort/Group problem with null-value rows

Hi,

If one or more rows are missing data in a column, sorting and grouping on this column won't work properly.

In the printscreen below, I have attempted to sort the contents of the ReportControl by clicking on the column header for the column labeled "String". It seems that the ReportControl isn't able to properly distinguish between rows that actually do have a value and rows that don't (i.e. the value is null). Instead, it mixes these together, resulting in a list where the rows are incorrectly sorted.


The next printscreen shows that grouping on a column which contains both ordinary values and null-values can result in multiple groups with identical criteria. (In this example, we have two groups where both groups are defined by having the value null in the column "String". (This can also happen to other values than null.))


Is this a known problem with the ReportControl?
Or is there a way to make ReportControl handle such null-value rows? (Preferrably without having to go through each combination of column and row in order to replace the value where such a null-value occurs...)

Hi,

don't know if this is normal behaviour of ReportControl but you can use SortPriority and GroupPriority to enforce correct sorting/grouping - see attached sample. uploads/3156/Grouping_NULL_values.zip

The sample assumes a simple booking list by a hotel: some arrival dates are not confirmed (NULL) and some room categories are NULL. Providing SortPriority/GroupPriority manually you can achieve expected sorting/grouping.

Peter