I'm working on a complex SSRS report that contains a number of subreport, with a total of five levels of nested sub-reports. This is a lot, but necessary due to the complicated nature of the top level report.
I've encountered an odd error with the last subreport I've added:
Warning 1 [rsErrorExecutingSubreport] An error occurred while executing the subreport 'ThingRateQuotaWrapper' (Instance: T0R0S0S1T0R0x0S0): Object reference not set to an instance of an object. C:\Users\mmxxxxxxx\Documents\Visual Studio 2012\ThingsReporting\ThingsReporting\Thing 2014 Consolidated Report.rdl 0 0
The problem here is that when I run the second level report (one of the reports contained in the top level "consolidated" report), everything works fine. But in the top level report, I get this unepected error.
The specific subreport mentioned is four levels down from the top report, so I would expected the second level report to fail if there was an issue, however as just mentioned that works perfectly.
In addition, the RDL and line number mentioned in the error message tells me nothing useful.
I've tried everything I can think of to solve this problem, including deleting, saving, re-inserting and configuring all the subreports from the ThingRateQuotaWrapper upwards. At this point I can think of nothing else to try that makes any sense.
How can a report fail because of a sub report four levels down, when other reports in between work correctly?
Anyone got any ideas or tips? I'm using SQL Server 2012 Business Intelligence and Visual Studio Premium 2012.
I've solved this problem, however I don't entirely understand the solution so I welcome any comments which might expand on it.
My approach was to look through each expression in the set of reports and subreports that make up my consolidated report, looking for any that might fail for any reason. I discovered that the visibility expression for the tablix row which contains the ThingRateQuotaWrapper subreport had the dreaded red squiggly line beneath it.
I believe the cause of the field warning is that the visibility expressed used a dataset other than the primary dataset of the tablix. I reworked the tablix dataset to contain the required column to determine visibility of the subreport, then updated the visibility expression to use the new column in the primary dataset. This fixed the problem.