Error: The base class includes the field <>, but its type…

Im getting this parser error:

 

The base class includes the field ‘gridResults’, but its type
(Infragistics.WebUI.UltraWebGrid.UltraWebGrid) is not compatible with the type
of control (Infragistics.WebUI.UltraWebGrid.UltraWebGrid).

 

Basically i had an asp.net website and everything was working fine. I realized i needed to use a web application instead so created a new project and copied over all the files from the web site. I added all the references and made the changes needed but i can’t figure out why i’m getting this. I’m using the ultrawebgrid version Version=9.1.20091.1015. Any ideas??  I can post code if needed. I found similar errors on google but they were all from years ago and had hotfixes.

OK i finally figured out after 90 minutes. When i created the web application i manually added references to the infragistics dlls. I guess i have two versions of the controls installed on my computer so i added the Infragistics2 dll in instead of the Infragistics35, which is what the website had been using. That was wreaking havoc on my grids since they were registered in the markup with the 35 assembly. Still the wording of the error made it cryptic to figure out…