Report Viewer Control (Web) Shows Blank Report

My solution to this issue was related to trying to set the report viewer height to 100%. This resulted in no report showing. Changing the height to a px value (ie 900px) got the reportviewer working.

There is this blog entry on MSDN that discusses how asynchronous rendering works.

Additionally, it mentions that (as was said in the comments) synchronous rendering embeds the content in the page, while asynchronous rendering renders the content in a frame. The size of the frame is "difficult...to calculate" and the SizeToReportContent property is ignored.

Since your report won't display unless it is synchronously rendered, the issue must be in the use of frames.

In the article mentioned in the comments, asynchronously rendering the report will collapse the control height to zero pixels if a relative height is used. This could explain why nothing is displayed. You might try specifying a height for the control. There are other suggestions in that article as well.

That's assuming that your issue is in the SQL Server 2008 R2 SSRS version, which I believe draws from VS 2008. SQL Server 2012 SSRS I think draws on VS 2010, which is not supposed to have those issues, so when you finish your upgrade, this issue might go away.

I had exactly the same symptom: A report was rendered with a completely blank page. For me that was the case in production, but it worked in development environment.

The report had two parameters and in the RDL both without having default values specified. When calling the report in the aspx code behind I had accidentally passed only one parameter. The second parameter had a default value set on the Report Server of the development machine but not in production. (Yes, the Report Server allows to specify parameter defaults independently from the default settings in the RDL file.) As a result the report rendered in development but not in production.

I found this by looking at the response XML with Fiddler. It contained an element telling me that a parameter value was invalid. Unfortunately the Report Viewer itself doesn't show any error message about the missing parameter and just displays a blank page - which makes the root of the problem difficult to find.