Write entire XML fragments in MSBuild with XmlPoke
I recently needed to write an entire project file via a targets (weird, I know). I was dreading all the crazy angle brackets escaping as
<
and >
when I decided to check the latest official docs on XmlPoke to refresh the parameters and format. To my surprise, I found this example:<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<Namespace>
<Namespace Prefix="dn" Uri="http://schemas.microsoft.com/appx/manifest/foundation/windows10" />
<Namespace Prefix="mp" Uri="http://schemas.microsoft.com/appx/2014/phone/manifest" />
<Namespace Prefix="uap" Uri="http://schemas.microsoft.com/appx/manifest/uap/windows10" />
</Namespace>
</PropertyGroup>
<Target Name="Poke">
<XmlPoke
XmlInputPath="Sample.xml"
Value="MyId"
Query="/dn:Package/mp:PhoneIdentity/@PhoneProductId"
Namespaces="$(Namespace)"/>
</Target>
</Project>
Notice how the
$(Namespace)
property has beautiful XML inside. Which only makes sense, since, there had to be some advantage in MSBuild being XML, right? So I figured, if the namespaces can be a full nested XML element, could the Value
be too? And the answer was a resounding YEAHHH: <PropertyGroup>
<UserPropertyGroup>
<PropertyGroup>
<ActiveDebugProfile>$(StartupFile)</ActiveDebugProfile>
</PropertyGroup>
</UserPropertyGroup>
</PropertyGroup>
<XmlPoke XmlInputPath="$(MSBuildProjectFullPath).user"
Value="$(UserPropertyGroup)"
Query="/msb:Project"
Namespaces="$(UserProjectNamespace)"/>
That writes an entire
<PropertyGroup>
element into a .user project file!For the attentive reader: you'd think I made a mistake, since, in XML-land, elements inherit the XML namespace of their parent element. Seems like the XML namespace management in XmlPoke is a bit on the loose side of things: the above snippets are in a .targets file without any xmlns (it's an SDK-style
<Project>
without namespace, to keep it clean. Yet, the property group is added without messing up the namespace:<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<ActiveDebugProfile>Program.cs</ActiveDebugProfile>
</PropertyGroup>
</Project>
If it had inserted it without a namespace, per the XML spec, it should have added an
xmlns=""
to clear the parent Project node namespace. But alas, it didn't, and in this particular case, it makes it way more convenient this way :).I'm using this in SmallSharp to initialize the .user project options properly with the right startup file for multi-startup top-level statements scripts in a single project :).