For a couple of hours I have been banging my head against the wall (still not literally, but I will start soon if I don't find a solution). For me, the problem I am facing actually is not a problem, cannot be a problem, because I use subreports successfully in another menu of the same Silverlight project, that I am working on. I even cannot define what it is - an issue, a problem, an evil... Crystal Reports sometimes can be ... well, interesting. Including the fact, that I have been working with CR for only 2 weeks (still learning while working) and the situation is just wonderful. Anyway.
First of all, I am trying to basically have two copies of a report per document. In the reports' Command (via Database Expert) I simply have select * from Documents where {?filter}. I give the where clause from C#, before I call ExportToDisk() method. There is an <sdk:DataGrid></sdk:DataGrid>, where I take all marked rows (docs) from, their RowIDs to be precise, create an 'in ()' clause, give it to the ?filter param of the report and it is working as I expect.
I searched on the web and the best I could find was to have a 'dummy' main report with its Section divided into two parts and insert my report as a subreport into those parts. So far, so good. I did the 'linking of params' (Change Subreport Links... option), as I did in the other menu and ... no data. Only the labels are showing. I checked 3 docs to be reported and i got 3 * 2 = 6 pages in total, but all with empty fields.
Final conclusion after more than an hour of testing: if I have a report and set it's Command via Database Expert to select * from Documents where RowID = '<someGuid>' or select * from Documents where {?filter}, then I always get all fields of the documents (like Customer, Code, etc.) - in the first case only one page for the particular doc, in the second case - one page per doc.
If I try as subreport and select 2 docs from the grid, I get four 'empty' pages - two per doc. No need to say, that if the subreport's command is: select * from Document where {?filter} and I link the filter with the main report, it's not working.
To my surprise, it seems to be working!... in one particular use case: if I set the command of the subreport to select * from Documents where 1 = 1. In this case, I get say 2000 pages for the 1000 docs I have in the table - all with all fields filled with data.
So this is my 'problem'!? It's so weird, that I even don't know should it be called a 'problem' or something else. Any help would be greatly appreciated.
edit: To summarize a bit: I have a main 'dummy' report with its command set to select * from Documents where {?filter}. I divide its Details section into two parts and I insert a subreport in each part. The command of the subreport is select * from Documents where doc_RowID = '{?filter}', where the RowID should come from the main report via linking. I tried in the subreport: select * from Documents where doc_RowID = '<someGuid>' and again I get pages with labels only. It 'works' if I have where 1 = 1 in subreport.
In main report, I even tried to group the docs by doc_RowID column and put the subreport in the GroupHeader and GroupFooter section. No success.
edit from today (21.12.2016): I tried to set the Command of the subreport to filter the data by some field of a left-joined table docItems as di, which shows the items bought: where di.Price > 5. When I run the query with this where clause in SQL Server Management Studio, I get a result of 7 records in 3 documents. In the report, I get 260 pages, which means, that it returns 130 documents within CR. WTF is going on here... :O
edit3: The customer's SQL server is down, so I decided to keep testing on our server. The problem disappeared. This may sound like a good news, but eventually, I will have to deploy my work to their server...
I have found the Magic for this. I call it 'Magic', because I don't know neither how exactly did it help in the situation, nor would it help next time I face a similar issue. I hope it doesn't happen.
Read this thread - there I found the solution. Just in case it gets dead, I will post it here: