SelectNodes() call on XMLDocument returning nothing

Question

I have the following simple XML File:

    <?xml version="1.0" encoding="utf-8"?>
<!--
This file is used by the publish/package process of your Web project. You can customize the behavior of this process
by editing this MSBuild file. In order to learn more about this please visit http://go.microsoft.com/fwlink/?LinkID=208121. 
-->
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <WebPublishMethod>FileSystem</WebPublishMethod>
    <LastUsedBuildConfiguration>Release</LastUsedBuildConfiguration>
    <LastUsedPlatform>Any CPU</LastUsedPlatform>
    <SiteUrlToLaunchAfterPublish />
    <LaunchSiteAfterPublish>False</LaunchSiteAfterPublish>
    <ExcludeApp_Data>False</ExcludeApp_Data>
    <publishUrl>E:\PublishTest</publishUrl>
    <DeleteExistingFiles>True</DeleteExistingFiles>
  </PropertyGroup>
</Project>

And am trying to change the value of one of the elements by doing the following:

XmlDocument xDoc = new XmlDocument();
xDoc.Load(fullPathToPortalPublishSettings);

// Change the publish url to be the one we want
var a = xDoc.SelectNodes("/Project/PropertyGroup");

But it always bombs out. I've removed the comments at the top of the XML file, I've tried just /Project, just Project, and I just can't seem to understand what is going wrong. I've looked at other posts, but don't see what is wrong with mine. Any idea? Thanks!

lose the trailing slash to make it /Project/PropertyGroup or actually select the children: /Project/PropertyGroup/* — Kris
Sorry, I should have mentioned I tried "xDoc.SelectNodes("/Project") as well, and even that pulls back nothing. — skaz
have you inspected xDoc in a watch? does it contain what you expect? — Kris
Yes, it has the document there with the root being #document. I don't know what is going wrong, though. — skaz
ah, namespaces...@see stackoverflow.com/questions/4171451/… — Kris

Kris Kris · Accepted Answer · 2016-10-11T11:43:48

You're querying a document that has a namespace so you need to address that in your code as well. so use a nametable, register the msbuild namespace under some namespace and use that like so:

XmlNamespaceManager manager = new XmlNamespaceManager(xDoc.NameTable);
manager.AddNamespace("msb", "http://schemas.microsoft.com/developer/msbuild/2003");
var nodes = xDoc.SelectNodes("//msb:Project/msb:PropertyGroup", manager);

or similar.

SelectNodes() call on XMLDocument returning nothing

1 Answers