title: Can't include extended WPF-Toolkit
body: <p>I would like to use the extended wpf toolkik(<a href="https://wpftoolkit.codeplex.com/" rel="nofollow noreferrer">https://wpftoolkit.codeplex.com/</a>) but I am too stupid to include it.</p>
  
  <p>I followed these steps:</p>
  
  <ol>
  <li>Reference the binaries in your project:<br>
    Reference WPFToolkit.Extended.dll in your project (Xceed.Wpf.DataGrid.dll for the 
    datagrid control)   </li>
  <li>Add a using statement ("using Xceed.Wpf.Toolkit;" for most of the controls, "using
  Xceed.Wpf.DataGrid;" for the datagrid control) to the top of .cs files  </li>
  <li>Add a new xmlns (xmlns:xctk="http://schemas.xceed.com/wpf/xaml/toolkit" for most of the controls,
  xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid" for the datagrid control) to the top of XAML 
  files</li>
  </ol>
  
  <p>The using-statement in the cs-file is working! But in my xaml-file I can´t find the toolkit!</p>
  
  <p>I added this: <code>xmlns:toolkit="http://schemas.xceed.com/wpf/xaml/toolkit"</code><br>
  but this namespace does not exist.</p>
  
  <p><a href="https://i.stack.imgur.com/bxcCH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bxcCH.png" alt=""></a>
  </p>
  
  <p>so what are I am doing wrong?</p>