Report Viewer Fun And Games

I had my first foray into the Report Viewer control today. It's been a couple of hours worth of fun :-) The point of this post is to share the resolution to the two problems that wasted the most of my time.

1)An object data source may not appear in the Website Data Sources window when you try to set the object data source for a SQL Server 2005 Reporting Services report in Visual Studio 2005. I couldn't understand why the buttons in the Website Data Sources window were greyed out. It turns out to be a known bug and the hot-fix for it is at http://support.microsoft.com/kb/939768



2) The 'XXX' parameter is missing a value : There are loads of posts for this and none of the posts I read supplied the resolution that fixed my particular problem. I was trying to set the parameter of a local report in the page load handler. When I views the page I kept getting the error message. When I tried to set a breakpoint, the code was not being hit, which lead me to believe that something fundamental was happening way earlier in the process. I reasoned that there was a null check being carried out and failing the code before my code to set the parameter was being called. I wondered if there was any way to allow nulls, and there was (is).




In the Report Parameters dialogue box there is a Check box labelled Allow null value. Selecting this solved my problem.