SSRS '08 Object reference not set to an instance of an object

Question

Full error from Preview window in Visual Studio '08 (BIDS): "An error occurred during local report processing. Object reference not set to an instance of an object."

There are no further errors/warnings detailed in the Error List or Output windows.

Background: On this report I am using a table to display a sub-report [x] number of times, dependant on the number of related objects that exist in the SQL database. That is to say that the sub-report is set within one of the cells (the only cell) of the table, in a row that repeats for each item returned in a dataset.

Removing the sub-report allows the master report to compile and run, so I feel the issue is related to the arrangement of the sub-report. If the sub-report only displays once, then the master report compiles and runs fine, it is only when a second instance is required that the issue arises.

When testing the sub-report separately, it compiles and runs when given the parameters for each instance it is being asked to render from the master report. So I can rule out the idea that the data for the second instance is causing it to fail (in some div-by-0 type way).

Given the lack of detail from the error and that the sub-report works on it's own, I do not understand why this is happening.

Does anyone have any ideas for debugging or suggested solutions?

Thanks

Brian

tldr: Master report fails when a sub-report repeats more than once.

Answer 1

I figured out a solution. The sub-report is being passed 4 parameters, one of these had a value referring to the value a table-cell on the master report. Changing this parameter to be the value of the expression that was setting that table-cell fixed the issue. I have no idea why this is a solution, but it is.

In more detail: [table_cell_a] had an expression computing it's value. [parameter_a] for the sub report was set as "=ReportItems("[table_cell_a]").Value", when I changed the expression for [parameter_a] to mirror the expression for [table_cell_a], everything worked again.

This is messed up, and I can't even begin to understand why it behaves like this. If [table_cell_a] was not being computed before the calls were made to the sub-reports, I could understand. But if that was the case, how come the report worked when there was only one sub-report?

If anyone can provide an explanation, I would be most grateful.

Brian

Answer 2

Brian,

I'm having a similar issue with charts imbedded in a Tablix. I found this article that seems to address the issue, although I have not gotten the server upgraded yet to actually test it:

http://support.microsoft.com/kb/2639301

Hope that helps.

G

Answer 3

I was getting the similar error after changing the names of reports in my project even though I changed all the updated report names in the Action property.

An error occurred during local report processing. Object reference not set to an instance of an object.

I found a solution by running the dataset of linked report providing the parameter values manually.

I am not sure what difference it made by running the dataset of linked report manually but it solved my problem and I am no longer getting this error.

Thanks

Yogi

Answer 4

Just sharing. In my case, it was not a sub-report. I had the same message when I was accessing a drill-through-report. Apparently, at the "Action: Go to report" > "Specify a report:", I have wrongly pasted the full name of the report with the extension. Removing the ".rdl" extension solved my problem.

Addendum: If the drill-through report name is part of an expression then the .rdl extension is necessary for it to work when hosted in SharePoint. That prevents it working in preview mode, as you've found. Solution is to code to avoid having to use an expression for the report name.

Answer 5

Copy the Dataset and Queries. Create new report or copy paste Tablix to new report. You will not get the error again.

Answer 6

I had to remove the SubReport and add it again. Then it worked.

Answer 7

I had the same error when I changed the name of the report I drilled to. I did change the name in the action expression to the new name via the properties > Action > Go to Report > (...) > Expression, but that apparently didn't take. When I opened the text box > Properties dialog window instead of using the Properties pane, and changed the drilled to report name within that window, it solved my issue.