I came across an annoying problem when playing with the ASP.NET Ajax extensions earlier today.  I was trying to call a script-enabled web-service but kept getting a javascript error telling me my service was undefined.  It’s been a month or so since I’ve used MS Ajax and needed a refresher.

Some background:

• My project namespace is ajaxTest
• My webservice class is helloTest
• My webservice function is helloWorld

I enabled the web service using the [System.Web.Script.Services.ScriptService()] attribute

I put the script manager code block in place and included a reference to the service.

<asp:ScriptManager ID=”ScriptManager1″ runat=”server”>
<Services>
<asp:ServiceReference Path=”helloTest.asmx” />
</Services>
</asp:ScriptManager>

I then created some javascript to call the web service

function testScriptService()
{
var tmp = helloTest.helloWorld(onResult, onTimeout, onError);
}

It was at this point I received the “helloTest is undefined” message.

A quick search on google revealed two websites which helped me.  The first had the right answer (in my situation).  Strangely, the second website had a slightly different solution which seems to have helped a number of people, but I was unable to figure out why (I didn’t work for me).

So, the solution that worked:

You need to fully qualify the javascript with the namespace of your webservice.

Namespace.Class.Function >> ajaxTest.helloTest.helloWorld

The solution which didn’t work for me but has worked for others is to use the following structure:

Namespace.Services.Class.Function >> ajaxTest.Services.helloTest.helloWorld

No idea why the difference, but hey.

Credit where credit’s due, thanks to Omen’s blog and Ryan at Solutek.