How to call extension methods using Eval in a databound control

I have a simple extension method on the int type so I can do the following:

string timeLength = 61.ToTime() // timeLength will be "1:01"

This works great in code, but I want to use this extension method in a Repeater Template. When databinding I want to do the following:

<%# Eval("LengthInSeconds").ToTime() %>

That didn't work so I tried:

<%# ((int) Eval("LengthInSeconds")).ToTime() %>

and it still didn't work. The JIT compiler is not seeing my extension method and I do have the proper import statement in the page.

My only idea for solving this is to replace the Eval with a Literal control and call the extension method in the code-behind, but either way, I would still like to know why this isn't working.

Thanks

From stackoverflow

• Does Eval("LengthInSeconds") work by itself?

  Scott Muc : Yes, that just returned the int in string form.

• Looks like I get to answer my own question! Asp.Net was compiling the .aspx,.ascx templates using the .Net 2.0 compiler. I needed to add the following to my web.config to make it work

    <system.codedom>
      <compilers>
        <compiler language="c#;cs;csharp" extension=".cs" type="Microsoft.CSharp.CSharpCodeProvider,System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" warningLevel="4">
          <providerOption name="CompilerVersion" value="v3.5"/>
          <providerOption name="WarnAsError" value="false"/>
        </compiler>
      </compilers>
    </system.codedom>
  

  I still have to perform the cast to (int) in the Eval, but that at least makes sense to me.

  Blakomen : This was *exactly* what I was looking for - thanks heaps!

• I had the same problem, and eventually found the solution.

  In my case I had forgot to import the namespace of my Extensionmethod-class. Even though the code behind page included the namespace, the aspx-page did not.

  I just added the namespace in the web.config file:

  and voila!!

  Darius Kucinskas : link for documentation http://msdn.microsoft.com/en-us/library/ms164642.aspx and example:

• The namespace declaration is done beneath the pages element in the web.config file like this:

  <pages styleSheetTheme="Default">
        <namespaces>
          <add namespace="MyNamespace"/>
        </namespaces>
  

• Another solution which solved it for me (which is similar to Patrik's), is to just import the namespace on that specific control or aspx page.

  <%@ Import Namespace="My.Namespace.Containing.MyExtensions.Class" %>
  

  This solution was more appropriate with my problem as the extension methods were only for a class used in the one control.