XPath for element with namespace

Question

What is the XPATH for attribute newVersion in the element

<dependentAssembly>
<assemblyIdentity name="System.Reactive.Linq" publicKeyToken="31bf3856ad364e35" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-2.2.5.0" newVersion="2.2.5.0" />
</dependentAssembly> 

I have tried my best to do it by myself. But don't know how to get XPATH for elements with namespace. Its very confusing. Somebody please provide me a XPATH.

XPATH which I came up with is

/configuration/runtime/assemblyBinding/dependentAssembly[2]/bindingRedirect[@newVersion='2.2.5.0']/@newVersion


<?xml version="1.0" encoding="utf-8"?>
<configuration>
<runtime>
<legacyUnhandledExceptionPolicy enabled="1" />
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
  <dependentAssembly>
    <assemblyIdentity name="System.Reactive.Interfaces" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect name="Test1" oldVersion="0.0.0.0-2.2.5.0" newVersion="2.2.5.0" />
  </dependentAssembly>
  <dependentAssembly>
    <assemblyIdentity name="System.Reactive.Linq" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-2.2.5.0" newVersion="2.2.5.0" />
  </dependentAssembly>      
</assemblyBinding>

Answer 1

In XSLT 1.0 you must declare namespaces with a prefix in order to be able to use them in XPath.

For example (wrapped for legibility):

<xsl:stylesheet 
  version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  xmlns:asm="urn:schemas-microsoft-com:asm.v1"
>
  <xsl:template match="/">
    <xsl:value-of select="
      /configuration/
       runtime/
       asm:assemblyBinding/
       asm:dependentAssembly[2]/
       asm:bindingRedirect[@newVersion = '2.2.5.0']/@newVersion
     " />
  </xsl:template>
</xsl:stylesheet>

However, you don't have to specify the entire path, you could take shortcuts:

<xsl:value-of select="
  //asm:assemblyIdentity[@name='System.Reactive.Linq']/
    asm:bindingRedirect[@newVersion = '2.2.5.0']/@newVersion
" />

Answer 2

The right xpath is

XPATH:

/configuration/runtime/ns:assemblyBinding/ns:dependentAssembly[ns:assemblyIdentity[@name='System.Reactive.Linq']]/ns:bindingRedirect/@newVersion

Where ns is the namespace urn:schemas-microsoft-com:asm.v1

I use a XmlPoke Task in the MSBuild tasks in the project file to modify the binding redirect. Together with a XmlPoke Task the code goes like this:

 <XmlPoke XmlInputPath="$(DestXmlFiles)" 
          Namespaces="&lt;Namespace Prefix='ns' Uri='urn:schemas-microsoft-com:asm.v1' Name='DoNotKnowWhatThisIsFor-ButItIsRequired' /&gt;"
          Query="/configuration/runtime/ns:assemblyBinding/ns:dependentAssembly[ns:assemblyIdentity[@name='System.Reactive.Linq']]/ns:bindingRedirect/@newVersion"
          Value="$(BUILD_NUMBER)"/>