Home / Community & Support / Developer Productivity Tools Forums / ASP.NET AJAX > Grid > Filter with MS DropDownList concept Issue - Unknown Server Tag

• Patrick

  Posted on Aug 28, 2008 (permalink)

  I need a little bit of insight on an "Unknown Server Tag" issue coming from the Filtering with MS DropDownList tutorial located at (http://www.telerik.com/help/aspnet-ajax/grdfilteringwithdropdownlist.html). 
  
  I've copied the Source provided there letter-for-letter to "Show Off" the RADGrid's capabilities compared to others.  However, there are a few warnings and parser errors that are halting the development:
  
  In designer, the gridview renders fine and the custom columns are editable.  However at runtime the ASPX page displays a parser error for an unknown server tag custom:MyCustomFilteringColumn.
  
  The two warnings in question are:
  
  Element 'MyCustomFilteringColumn' is not a known element. This can occur if there is a compilation error in the Web site, or the web.config file is missing.
  
  and
  
  Generation of designer file failed: Unknown server tag 'custom:MyCustomFilteringColumn'
  
  The one time it did not give these errors, it complained that columns about the column type. 
  
  Any insight on this?  I'm using the Trial version at the moment, and the code is a carbon copy from the URL provided above.  Development environment is Visual Studio 2008 with Service Pack 1.
  
  Thanks for the support.
  

  Reply

• Plamen Peshev Plamen Peshev

  Posted on Aug 28, 2008 (permalink)

  Hello Patrick,
  
  
  At the top of the the ASPX page, register the namespace for the custom column class. Here is an example:
  
  <%@ Register Namespace="MyStuff" TagPrefix="custom" %> 
  
  If you need additional assistance, do not hesitate to contact me
  
  
  
  Greetings,
  Plamen
  the Telerik team

  
  Check out Telerik Trainer, the state of the art learning tool for Telerik products.

  Reply


• Patrick

  Posted on Aug 28, 2008 (permalink)

  The @Register entry is there with both the namespace and TagPrefix attribute copied directly from the tutorial page.  Unfortunately, it's still not recognizing the server tag. 
  
  As additional information, the properties window in source view displays properties for GridBoundColumn tags, however for the MyCustomFilteringColumn tags only < HTML ELEMENT > is being displayed.
  

  Reply

• Plamen Peshev Plamen Peshev

  Posted on Aug 29, 2008 (permalink)

  Hello Patrick,
  
  
  I tried to reproduce the problem at our side, but to no avail. Can you please open a new support ticket and send us a small sample project where the problem can be observed?
  
  Thanks for your cooperation.
  
  Sincerely yours,
  Plamen
  the Telerik team

  
  Check out Telerik Trainer, the state of the art learning tool for Telerik products.

  Reply

• Nathan

  Posted on Sep 16, 2008 (permalink)

  Did you find a solution to this, as I am experiencing the same thing.

  Reply

• Kim

  Posted on Oct 3, 2008 (permalink)

  I have found the same problem.  Did anyone get back you?

  Reply

• Sebastian Sebastian

  Posted on Oct 3, 2008 (permalink)

  Hello guys,
  
  You can use the version from your local RadControls installation of this online demo of RadControls for ASP.NET AJAX:
  
  http://demos.telerik.com/ASPNET/Prometheus/Grid/Examples/Programming/FilteringTemplateColumns/DefaultCS.aspx
  
  or the forum thread linkes below (converting the solution to use the ASP.NET AJAX version of the grid):
  
  http://www.telerik.com/community/forums/thread/b311D-ecghh.aspx
  
  Best regards,
  Stephen
  the Telerik team

  
  Check out Telerik Trainer, the state of the art learning tool for Telerik products.

  Reply

• immitev

  Posted on Dec 10, 2008 (permalink)

  I had the same issue, and the problem was in the Register directive where Assembly is actually obligatory field.
  
  If you use it in multiple places you might add it directly in the web.config:
  
  

  <system.web>

  <pages validateRequest="false">

  <controls>

  <add tagPrefix="custom" namespace="YourNamespace" assembly="YourAssembly" />

  </controls>

  </pages>

  
  

  Reply

• Yeroon

  Posted on Dec 18, 2008 (permalink)

  I resolved it by adding the Assembly name.
  
  <%@ Register Namespace="MyStuff" TagPrefix="custom" Assembly="MyAssembly" %>
  
  If you are not sure what the Assemblyname should be, go to the property pages of your project and look at the Application Tab.
  
  There is a textbox Assembly Name there. Use whats in the textbox.
  
  The example from telerik assumes a Website and not a Web Application project. Assembly required for the latter.

  Reply

• Ahrensberg

  Posted on Dec 11, 2009 (permalink)

  Thank you immitev and Yeroon. Solved my problem! ;o)
  

  Reply

• Warren

  Posted on May 19, 2010 (permalink)

  Wow, I am so happy I finally found this post...  Solved my problem perfectly,...

  Reply

• Santhosh

  Posted on Oct 9, 2011 (permalink)

  A simple problem with a simple solution wasted my time alot.
  Thanks.. solved it now by adding assembly name in register tag.

  Reply

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