How to ignore the property value given on the command line from within the respective csproj file? - msbuild

Question

Our TFS build controllers build all the projects from the same solution into the same shared bin directory, because the TFS build workflow passes the OutDir parameter to the msbuild command responsible for building the solution.
I have a project where I want to suppress this behavior and let it build into the standard relative bin\Debug or bin\Release directory.
But I cannot find how to do it. Indeed, observe the following trivial msbuild script:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<OutDir>$(MSBuildThisFileDirectory)bin\$(Configuration)</OutDir>
</PropertyGroup>
<Target Name="Build">
<Message Text="$(OutDir)" Importance="High"/>
</Target>
</Project>
Now, I am running it:
PS C:\> msbuild .\1.csproj /p:OutDir=XoXo /nologo
Build started 11/13/2015 9:50:57 PM.
Project "C:\1.csproj" on node 1 (default targets).
Build:
XoXo
Done Building Project "C:\1.csproj" (default targets).
Build succeeded.
0 Warning(s)
0 Error(s)
Time Elapsed 00:00:00.03
PS C:\>
Notice it displays XoXo, ignoring my attempt to override it from within.
So, is it possible?

Answer 1

This is a bit of a classic RTFM situation but interesting nonetheless. See the documentation for MSBuild Properties in particular the part on Global Properties and how to make properties not being overridden by the former:
MSBuild lets you set properties on the command line by using the /property (or /p) switch. These global property values override property values that are set in the project file. This includes environment properties, but does not include reserved properties, which cannot be changed.
Global properties can also be set or modified for child projects in a multi-project build by using the Properties attribute of the MSBuild task
If you specify a property by using the TreatAsLocalProperty attribute
in a project tag, that global property value doesn't override the
property value that's set in the project file.
It also links to the Project element documentation which basically repeats the same info and says multiple properties in the attribute should be seperated by semi-colons.
In short, code applied to your case:
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"
TreatAsLocalProperty="OutDir">
Note that this will completely disable altering OutDir from outside the project though. An alternate solution which is more configurable could be to have a small stub project which you make TFS build instead of the main project. In that project you can then decide on whether to pass OutDir to the actual project or override it, e.g. by fetching the value by importing a file which might or might not be defined, or based on an environment variable or so. This gives the basic idea:
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="12.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<!-- Try import if this file exists, it should supply the value for CustomOutDir-->
<Import Project="$(MSBuildThisFileDirectory)customoutdir.props" Condition="Exists('$(MSBuildThisFileDirectory)customoutdir.props')"/>
<PropertyGroup>
<!-- Default value for CustomOutDir if not set elsewhere -->
<CustomOutDir Condition="'$(CustomOutDir)' == ''">$(MSBuildThisFileDirectory)bin\$(Configuration)</CustomOutDir>
<!-- ApplyCustomOutDir specifies whether or not to apply CustomOutDir -->
<ActualOutDir Condition="'$(ApplyCustomOutDir)' == 'True'">$(CustomOutDir)</ActualOutDir>
<ActualOutDir Condition="'$(ApplyCustomOutDir)' != 'True'">$(OutDir)</ActualOutDir>
</PropertyGroup>
<Target Name="Build">
<MSBuild Projects="$(MasterProject)" Properties="OutDir=$(ActualOutDir)"/>
</Target>
</Project>
And should be invoked by passing the neede properties like
msbuild stub.targets /p:MasterProject=/path/to/main.vcxproj;ApplyCustomOutDir=True
(I have never used TFS so the way to get the properties passed might be different)