web.config transform not working - asp.net-mvc

Question

In an MVC application I have a web.config that is setup for my development environment, and I have a transform file that needs to insert a new WCF service endpoint, however it is adding it in the wrong place so I think I have missed something.
I have cut down on the config file to show only what is needed.
I have the normal web.config as follows:
<services>
<!-- Report Service -->
<service name="Core.ReportDataHost">
<endpoint name="ReportDataHost" address="..." binding="customBinding" contract="..."/>
</service>
<!-- Authentication Service -->
<service name="Core.AuthenticationHost">
<endpoint name="AuthenticationHost" address="..." binding="customBinding" contract="..."/>
</service>
</services>
I then have the transform file as follows:
<services>
<service name="Core.AuthenticationHost">
<endpoint xdt:Transform="Insert" address="" binding="customBinding" contract="..." />
</service>
</services>
I expected this to add the new endpoint in the "AuthenticationHost" service, but it adds it to the first service "ReportDataHost".
Any ideas what I am missing?

Answer 1

Transforms only use tags by default, not attributes, so even though you have name="Core.AuthenticationHost" in your transform, it is being ignored and only matching on the Service tag, using the first Service tag it finds.
Add a locator to the <service> tag so that it knows which one to use (instead of just using the first). The Locator is an attribute on the tag: xdt:Locator="Match(attribute1,attribute2,...)". In this case, you want to match on the name attribute.
Your corrected Transform will look like this:
<services>
<service name="Core.AuthenticationHost" xdt:Locator="Match(name)">
<endpoint xdt:Transform="Insert" address="" binding="customBinding" contract="..." />
</service>
</services>
More information is available on MSDN's Transform Syntax page.