title: WiX x86 / x64 build using Platform attribute
body: <p>I'm using following define to make my setup script flexible according to the build environment.</p>
  
  <pre><code>&lt;?if $(var.Platform)=x64 ?&gt;
  
  &lt;?define PlatformProgramFilesFolder = "ProgramFiles64Folder" ?&gt;
  &lt;?define win64Flag = "yes"?&gt;
  &lt;?define TargetConfigurationPath = "bin\x64\Release"?&gt;
  
  &lt;?else ?&gt;
  
  &lt;?define PlatformProgramFilesFolder = "ProgramFilesFolder" ?&gt;
  &lt;?define win64Flag = "no"?&gt;
  &lt;?define TargetConfigurationPath = "bin\x86\Release"?&gt;
  &lt;?endif ?&gt;
  </code></pre>
  
  <p>in detail I mind about the win64Flag variable which i use in every Win64 Attribute of components. I'm using the Platform in the Packages "Platform" attribute too.
  But to get back to the Win64 attribute, i use the variable this way:</p>
  
  <pre><code>Win64="$(var.win64Flag)"
  </code></pre>
  
  <p>And I always get a warning telling me that using this statement in a YesNoType attribute is invalid.</p>
  
  <p>I'm building this stuff using candle.exe with this call:</p>
  
  <pre><code>candle.exe -ext WixUtilExtension -dPlatform=x86 "Deployment\WiX Setup Project\SetupScript.wxs" -out "Deployment\TempBuildOutput\SetupScript x86.wixobj"
  
  light.exe -ext WixUIExtension -ext WixUtilExtension "Deployment\TempBuildOutput\SetupScript x86.wixobj" -out "Deployment\TempBuildOutput\Installer_x86.msi"
  </code></pre>
  
  <p>I got some CustomAction in my script, which auto-starts an application if the installation finished. This works fine on x64 builds, but not with x86 builds. 
  Thats why i think that there might be something wrong with the Win64 Attribute, or better, in the way how I use it. </p>
  
  <p>But according to my thoughts, something must be correct with this code, because the files are installed to the appropriate folder on x64 (Program Files) and x86 (Program Files (x86)). But i'm asking myself, whats the reason my apps are not started after the installation was finished.</p>
  
  <p>I'm working with a x64 Windows, can this be the cause of failing to start my x86 auto start apps?</p>
  
  <p>Is there a way on solving the warning on my usage of the Win64 Attribute?</p>