title: Helix 3D Toolkit: Not accessible in xaml
body: <p>I want to use Helix 3d Toolkit in my WPF application with C#. From <a href="https://helixtoolkit.codeplex.com/releases/view/76036" rel="nofollow noreferrer">site</a> today I downloaded HelixToolkit-2014.1.2.1.zip and extracted in a folder. It contains folders for NET 4.0 &amp; 4.5 respectively. </p>
  
  <p>In my application, I added reference for HelixToolkit.Wpf.dll and tried to access in xaml. Using an <a href="https://stackoverflow.com/questions/12793037/drawing-a-3d-pipe-using-wpf">example as reference</a> I started creating xaml.</p>
  
  <pre><code>&lt;Window x:Class="Learn3DApp.HelixExamples"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:helix="clr-namespace:HelixToolkit.Wpf;assembly=HelixToolkit.Wpf"
      Title="HelixExamples" Height="300" Width="300"&gt;
  &lt;Grid&gt;
      &lt;helix:HelixViewport3D x:Name="mainViewPort" &gt;
  
      &lt;/helix:HelixViewport3D&gt;
  &lt;/Grid&gt;
  </code></pre>
  
  <p>On <code>&lt;helix:HelixViewport3D</code> line I get error "The name HellxViewport3D does not exist in the namespace "clr-namespace:HelixToolkit.Wpf;assembly=HelixToolkit.Wpf". The clr line is not underlined, but  is underlined and the error also appears in that line only.</p>
  
  <p>In code behind I tried and could add <code>using HelixToolkit.Wpf;</code> and also access HelicViewport3d easily without any problem. </p>
  
  <p>My project is of Target Net 4.5, I tried adding HelixToolkit of 4.0 and 4.5 also (1 after another). But same problem in both the dlls'. Why so ?? I am using VS 2012.</p>
  
  <p>What seems to be the problem ? Am I missing anything OR clr is not proper ??? OR is this Helix version not proper - which one to use ?? 
  I am stuck and not able to move ahead. Have spent almost half day figuring the problem. If anyone can help me out, it would be great.</p>
  
  <p>Thanks</p>