get windows sdk directory from registry in msbuild test

getsdkdir.proj

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
	<Choose>
		<!-- I could not find key of v8.1 in HKCU -->
		<!-- if you want to support another SDK version,add When directive(Entry at the top will be priority) -->
		<!-- for windows sdk 8.1A-->
		<When Condition="'$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v8.1A@InstallationFolder)' != ''">
			<PropertyGroup>
				<MyWindowsSdkDir>$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v8.1A@InstallationFolder)</MyWindowsSdkDir>
			</PropertyGroup>
		</When>
		<!-- for windows sdk 7.1-->
		<When Condition="'$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v7.1\@InstallationFolder)' != ''">
			<PropertyGroup>
				<MyWindowsSdkDir>$(Registry:HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SDKs\Windows\v7.1\@InstallationFolder)</MyWindowsSdkDir>
			</PropertyGroup>
		</When>
	</Choose>
	<Target Name="Build">
		<Message Text="windows sdk dir is $(MyWindowsSdkDir)"/>
	</Target>
</Project>