How do I update an xml file with msbuild with two namespaces? - msbuild

Question

This msbuild below task can take into account one namespace, but in the case where I'm updating an mxml (flex) that has a mix of namespaces, can I use this task or another msbuild task to do the update?
<XmlUpdate
Prefix="fx"
Namespace="http://ns.adobe.com/mxml/2009"
XmlFileName="myFlexApp.mxml"
Xpath="//mx:Application/fx:Declarations/fx:String[#id='stringId']"
Value="xxxxx">
Here is the flex xml I'm trying to update:
<mx:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:mx="library://ns.adobe.com/flex/mx"
xmlns:s="library://ns.adobe.com/flex/spark">
<fx:Declarations>
<fx:String id="stringId">UPDATE_ME</fx:String>
</fx:Declarations></mx:Application>

Answer 1

I was able to successfully update the source for XmlUpdate so that it takes multiple namespaces:
if (!string.IsNullOrEmpty(_prefix) && !string.IsNullOrEmpty(_namespace))
{
string[] prefixes = _prefix.Split(';');
string[] namespaces = _namespace.Split(';');
if (prefixes.Length != namespaces.Length)
throw new Exception("The number of prefixes is different from the number of namespaces");
for (int prefixIndex = 0; prefixIndex < prefixes.Length; prefixIndex++)
{
manager.AddNamespace(prefixes[prefixIndex], namespaces[prefixIndex]);
}
}
This works with the example of
<XmlUpdate
Prefix="fx;mx"
Namespace="http://ns.adobe.com/mxml/2009;library://ns.adobe.com/flex/mx"
XmlFileName="myFlexApp.mxml"
Xpath="//mx:Application/fx:Declarations/fx:String[#id='stringId']"
Value="xxxxx">

Answer 2

You'll have to use XmlMassUpdate task. (This task is from MSBuild Community Tasks)
<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<!-- The replacement value is here -->
<!-- ProjectExtensions keep MSBuild to try to evaluate the content -->
<ProjectExtensions>
<ReplacementNode>
<String id="stringId">CHANGE</String>
</ReplacementNode>
</ProjectExtensions>
<Target Name="XmlUpdate">
<XmlMassUpdate
ContentFile="myFlexApp.mxml"
NamespaceDefinitions="msb=http://schemas.microsoft.com/developer/msbuild/2003;
fx=http://ns.adobe.com/mxml/2009;
mx=library://ns.adobe.com/flex/mx"
ContentRoot="//mx:Application/fx:Declarations/fx:String[#id='stringId']"
SubstitutionsFile="$(MSBuildProjectFullPath)"
SubstitutionsRoot="msb:Project/msb:ProjectExtensions/msb:ReplacementNode/msb:String"/>
</Target>
</Project>
Changing the value during execution
The tricky part is that you can't define a value on fly using XmlMassUpdate only, you'll need to use XmlUpdate to update the value in your replacement node first.
<?xml version="1.0" encoding="utf-8"?>
<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<!-- The replacement value is here -->
<!-- ProjectExtensions keep MSBuild to try to evaluate the content -->
<ProjectExtensions>
<ReplacementNode>
<String id="stringId">CHANGE</String>
</ReplacementNode>
</ProjectExtensions>
<Target Name="XmlUpdate" DependsOnTargets="ChangeXmlValue">
<XmlMassUpdate
ContentFile="myFlexApp.mxml"
NamespaceDefinitions="msb=http://schemas.microsoft.com/developer/msbuild/2003;
fx=http://ns.adobe.com/mxml/2009;
mx=library://ns.adobe.com/flex/mx"
ContentRoot="//mx:Application/fx:Declarations/fx:String[#id='stringId']"
SubstitutionsFile="$(MSBuildProjectFullPath)"
SubstitutionsRoot="msb:Project/msb:ProjectExtensions/msb:ReplacementNode/msb:String"/>
</Target>
<Target Name="ChangeXmlValue">
<XmlUpdate Prefix="n"
Namespace="http://schemas.microsoft.com/developer/msbuild/2003"
XPath="n:Project/n:ProjectExtensions/n:ReplaceNode/n:String/text()"
XmlFileName="$(MSBuildProjectFullPath)"
Value="$(NewValue)" />
</Target>
</Project>