All other tooltips work, but when you add it to the series, as soon as you hover the mouse over the chart the report errors out with “Parameter is not valid.” It turns out this only happens with Stepped graphs.
This only happens in Visual Studio. If you Preview the report, or press F5 to run it, you will get the same result. However, if you deploy the report to a report server, it runs fine without an error and the tooltip displays properly.
Easy to Reproduce
We investigated some more and were able to reproduce the problem on other PCs (all using Visual Studio 2010 / SSRS 2012). Obviously this is a bug in SSRS. You can easily recreate the problem yourself:
- Create a new report
- Put this query in your dataset:
SELECT 188292 AS ListingID, 4 AS NumLeads UNION ALL SELECT 179922,6 UNION ALL SELECT 77439,7 UNION ALL SELECT 185587,11 UNION ALL SELECT 78421,11 UNION ALL SELECT 188279,14 UNION ALL SELECT 85894,14 UNION ALL SELECT 44601,20 UNION ALL SELECT 12820,22 UNION ALL SELECT 183158,23
- Create a new chart in the report, a standard line graph
- Add NumLeads to the Values of the chart
- Go to the properties for the Series and set the Tooltip to Sum(NumLeads)
- Preview the report and confirm it displays properly
- Change Chart Type… to Stepped
- Preview the report and the error will occur
The workaround is simple: do not use a Stepped graph.
However, if you really want to use a Stepped graph, it may be possible. We were able to get a series tooltip to work on a Stepped graph in one instance. This was on a chart that had already been created and configured on an existing report. Apparently, if the chart is configured in certain ways, this problem will not occur. But with a newly-created chart, the error occurs every time. You may just have to fiddle with the settings to get it to work.
This is clearly a bug in SSRS. We submitted a bug report to Microsoft Connect. If you found this page because you experienced the same problem, be sure to go to Microsoft Connect and add your vote: https://connect.microsoft.com/VisualStudio/feedback/details/786718/parameter-is-not-valid-error-in-ssrs-report-after-adding-a-tooltip
Update: Microsoft responded to the bug report and said they no longer support problems with Visual Studio 2010. Oh well!
Special thanks to Lance England who helped me investigate this issue (check out his blog).