XPath select node with namespace

Its a .vbproj and looks like this

<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <ProjectGuid>15a7ee82-9020-4fda-a7fb-85a61664692d</ProjectGuid>

all i want to get is the ProjectGuid but it does not work when a namespace is there...

 Dim xmlDoc As New XmlDocument()
 Dim filePath As String = Path.Combine(mDirectory, name + "\" + name + ".vbproj")
 xmlDoc.Load(filePath)
 Dim value As Object = xmlDoc.SelectNodes("/Project/PropertyGroup/ProjectGuid")

what can i do to fix this?

I'd probably be inclined to go with ~~Bartek's~~* namespace solution, but a general xpath solution is:

//*[local-name()='ProjectGuid']

**since Bartek's answer has disappeared, I recommend Teun's (which is actually more thorough)*

The best way to do things like this (IMHO) is to create a namespace manager. This can be used calling SelectNodes to indicate which namespace URLs are connected to which prefixes. I normally set up a static property that returns an adequate instance like this (it's C#, you'll have to translate):

private static XmlNamespaceManager _nsMgr;
public static XmlNamespaceManager NsMgr
{
  get
  {
    if (_nsMgr == null)
    {
      _nsMgr = new XmlNamespaceManager(new NameTable());
      _nsMgr.AddNamespace("msb", "http://schemas.microsoft.com/developer/msbuild/2003");
    }
    return _nsMgr;
  }
}

I include only one namespace here, but you could have multiple. Then you can select from the document like this:

Dim value As Object = xmlDoc.SelectNodes("/msb:Project/msb:PropertyGroup/msb:ProjectGuid", NsMgr)

Note that all of the elements are in the specified namespace.

This problem has been here several times already.

Either you work with namespace-agnostic XPath expressions (not recommended for its clumsiness and the potential for false positive matches - <msb:ProjectGuid> and <foo:ProjectGuid> are the same for this expression):

//*[local-name() = 'ProjectGuid']

or you do the right thing and use a XmlNamespaceManager to register the namespace URI so you can include a namespace prefix in your XPath:

Dim xmlDoc As New XmlDocument()
xmlDoc.Load(Path.Combine(mDirectory, name, name + ".vbproj"))

Dim nsmgr As New XmlNamespaceManager(xmlDoc.NameTable)
nsmgr.AddNamespace("msb", "http://schemas.microsoft.com/developer/msbuild/2003")

Dim xpath As String = "/msb:Project/msb:PropertyGroup/msb:ProjectGuid"
Dim value As Object = xmlDoc.SelectNodes(xpath, nsmgr)

You need just to register this XML namespaces and associate with a prefix, to make the query work. Create and pass a namespace manager as second parameter when selecting the nodes:

Dim ns As New XmlNamespaceManager ( xmlDoc.NameTable )
ns.AddNamespace ( "msbuild", "http://schemas.microsoft.com/developer/msbuild/2003" )
Dim value As Object = xmlDoc.SelectNodes("/msbuild:Project/msbuild:PropertyGroup/msbuild:ProjectGuid", ns)

XPath select node with namespace

Related

Recent Posts