Why does my report require strings sometimes, and not others?

[Former Member]

I don't get this one.

I have Crystal Reports with Visual Studio 2005, and VB.NET.

I've created a report that takes in a List(Of PR) where PR is a .NET object encapsulating my records.

The form then looks up lists for a couple of other objects, List(Of PRAdditionalInfo) and List(Of PRLogEntry), populates subreports with those lists and members from the first list.

Everything works great for some List(Of PR) collections I send it -- including the list that comprises all of the available PRs -- but not for others. Sometimes I get this message and the report doesn't show up in the viewer:

A string is required here.

Error in File C:DOCUME~1\blahblah\...\Temp\...\SomeReallyLongString.rpt:

Error in formula <Record Selection>.

'{HardwareTrkr_PRAdditionalInfo.ProblemReportID} = {?Pm-HardwareTrkr_PR.ID_PR}'

A string is required here.

Why would strings be required sometimes but not other times? It's a puzzle to me but maybe there's an easy answer.

Thanks!

[Former Member · Accepted solution]

Answered my own question.

Some of the PRAdditionalInfo lists were empty. That was the difference.