Have you ever get one of the following error?
The server tag ‘ajaxControlToolkit:ControlX‘ is ambiguous. Please modify the associated registration that is causing ambiguity and pick a new tag prefix.
‘ControlX‘ is ambiguous in the namespace ‘AjaxControlToolkit’.
<controls> <add namespace="AjaxControlToolkit" assembly="AjaxControlToolkit, Version=3.5.11119.20050, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e" tagPrefix="ajaxContrlToolkit"/> <add namespace="AjaxControlToolkit" assembly="AjaxControlToolkit, Version=1.0.20229.20821, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e" tagPrefix="ajaxControlToolkit"/> </controls>
You can NOT have a same tagPrefix(here in this example ‘ajaxControlToolkit’) for two different version of same assembly. So if you set different tagPrefix, you will end up getting Error #2.
The reason is that you can NOT run two different version of AjaxControlToolkit dll or any assembly in same web application. It would work if you have two different web application and both are referencing different version.
Hope that helps you!!!