Hi I compared report rendering between Reportviewer 2008 and REportViewer 2010. I discovered a difference that causes a very noticeable increase in the html stream size : the css classes associated to each report element are now named with a sort of guid instead of a small id previsously. For example, for a report rendering a large table , the html stream weighs 250kb with REportViewer2008 and 550kb for reportviewer2010 (same data of course) . The rendering time is increased accordingly Is there a way to control how the style is applied or at least how the classes are named ? Thanks

Hi Concert051, Could you please eleborate a bit more about the scenario? How did you get the HTML stream? If you meant "View Source" of a page that contains a Report Viewer control, then the behavior you described should be expected, as Report Viewer 2010 supports more feature, such as AJAS supported. Thanks, Jin ChenJin Chen - MSFT

Hi Jen I measured the html stream using fiddler. I am aware the the new version uses ajax and this implies larger scripts to be downloaded to the browser. However, I don't understand why this script has to be loaded on every page refresh since the cache expiration attribute is set to make it expire immediately after download. I think a longer expiration time would be appropriate. Secondly, the html is formed differently from previous version (reportviewer2008). for example, each table cell is rendered with ReportViewer 2008 : <TD style="HEIGHT:6.61mm;" class="a26cr"><DIV class="a26">11/1/2010 12:00:00 AM</DIV></TD> with ReportViewer 2010 : <TD class="A172165c7e4ce48c1a58145e2dcc02b7727cr"><DIV class="A172165c7e4ce48c1a58145e2dcc02b7727">11/1/2010 12:00:00 AM</DIV></TD> this leads to a very longer stream with a large table for example. (in my test the stream grows from 250kb to 550kb for the same report&data) I wanted to know if there is a way to control how these css class are named. Thanks Lorenzo

Lorenzo - can you change the thread type to question from discussion? Thanks.Kalman Toth, SQL Server & Business Intelligence Training; SQL Server 2008 Training