title: How can I ignore optional parameter error on MSBuild 3.5
body: <p>I am using Visual Studio 2010.</p>
  
  <p>I've donwloaded an updated class (i.e. UpdatedClass.cs) which has a method with optional parameter, such as:</p>
  
  <pre><code>public void DoThis(bool aValue = false) {...}
  </code></pre>
  
  <p>Using Visual Studio 2010, I am able to compile it. But I cannot do it with MSBuild:</p>
  
  <pre><code>C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC&gt;C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe /t:Rebuild /clp:ErrorsOnly D:\folder\mySolution.sln
  ln
  Microsoft (R) Build Engine Version 3.5.30729.5420
  [Microsoft .NET Framework, Version 2.0.50727.5448]
  Copyright (C) Microsoft Corporation 2007. All rights reserved.
  
  UpdatedClass.cs(29,94): error CS0241: Default parameter specifiers are not permitted
  </code></pre>
  
  <p>Well, optional parameters are not permitted using this compiler. So can I add an extra argument in this MSBuild command, to ignore this kind of error?</p>
  
  <p>Or do I have to compile the project using <code>C:\WINDOWS\Microsoft.NET\Framework64\v4.0.30319\MSBuild.exe</code> ?
  Is this safe regarding asp.net projects?</p>