XPath expression to get the asssembly name from the type

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MSBuild

XPath

Struggling with this XPath expression, basically I need to extract the assembly name from a piece of xaml like this:

<Modularity:ModuleCatalog
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:Modularity="clr-namespace:Microsoft.Practices.Prism.Modularity;assembly=Microsoft.Practices.Prism"
    xmlns:AppInfo="clr-namespace:Example.Common.Services.Prism.Modularity;assembly=Example.Common.Services">
    <Modularity:ModuleInfoGroup InitializationMode="OnDemand">
        <AppInfo:ApplicationModuleInfo
            ModuleName="Administration"
            ModuleType="Example.UI.Administration.AdministrationModule, Example.UI.Administration, Version=1.2.1.1, Culture=neutral, PublicKeyToken=537c3450b3658434"
            Ref="Example.UI.Administration.xap" />
        <AppInfo:ApplicationModuleInfo
            ModuleName="Prescribing"
            ModuleType="Example.UI.Prescribing.PrescribingModule, Example.UI.Prescribing, Version=1.24.2.1, Culture=neutral, PublicKeyToken=537c3450b3658434"
            Ref="Example.UI.Prescribing.xap" />
        <AppInfo:ApplicationModuleInfo
            ModuleName="SampleModule"
            ModuleType="Example.UI.SampleModule.SampleModuleModule, Example.UI.SampleModule, Version=1.1.0.0, Culture=neutral, PublicKeyToken=537c3450b3658434"
            Ref="Example.UI.SampleModule.xap" />
    </Modularity:ModuleInfoGroup>
</Modularity:ModuleCatalog>

I am basically trying to get "Example.UI.SampleModule" etc. At the moment my expression is as follows:

.//*[local-name() = 'ApplicationModuleInfo']/@ModuleType[substring-after(., ',')][substring-before(.,',')]

But it appears as if the substrings are being completly ignored as the full type names are still found. I'm wondering if using "." as current transform is the correct thing to do?? I.e

substring-before(., ",")

is "." correct?