title: Reference name space in another project in WPF xaml file
body: <p>I am referencing to a namespace of another project(class library, where all the models resides).</p>
  
  <p>as mentioned in the related questions, they have sloved the probem by adding the assembly as well to the .xaml file. But this did not work for me. That is why I am posting.</p>
  
  <p>I have 2 projects.</p>
  
  <ol>
  <li>WPF project itself.</li>
  <li>Class Library(this has all the viewmodels)</li>
  </ol>
  
  <p>WPF project has a reference to the Class Library.(Which should create a dll file of this Class Library in the bin of WPF project)</p>
  
  <p>I want to refer to a model in the class library.
  So, I did as follows.</p>
  
  <pre><code>    &lt;UserControl x:Class="WPFApplication.Views.SalesScreen"
               xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
               xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
               xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
               xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
               xmlns:productListViewModel="clr-namespace: WPFApplication.CommonInterface.Shared.ViewModels; assembly=WPFApplication.CommonInterface"
               mc:Ignorable="d" 
               d:DesignHeight="820" d:DesignWidth="1280" Loaded="PlaneLoaded"&gt;....
  ....
  &lt;productListViewModel:ProductListVM x:Key="ProductsListVMC"/&gt;...
  </code></pre>
  
  <p>But still the problem exits, this <code>ProductListVM</code> class(model) exists in the <code>WPFApplication.CommonInterface.Shared.ViewModels</code> name space and it is <code>public</code> as well. :)</p>
  
  <p>the error says,</p>
  
  <pre><code>The name "ProductListVM" does not exist in the namespace "clr-namespace:WPFApplication.CommonInterface.Shared.ViewModels; assembly=WPFApplication.CommonInterface".
  </code></pre>
  
  <p>I also tried to seperately build the Class Library and add the dll file manually to the WPF project <code>bin/debug</code> and built it. but the problem exits as the same.</p>
  
  <p>there is another error in the error list as well.</p>
  
  <pre><code>Unknown build error, ''clr-namespace:WPFApplication.CommonInterface.Shared.ViewModels; assembly=POS.WPFApplication.CommonInterface' mapping URI is not valid. Line 7 Position 14.'  D:\Dev\WPFApplication\Views\POSViews\SalesScreen.xaml
  
  Error   1   The URI "clr-namespace:WPFApplication.CommonInterface.Shared.ViewModels; assembly=WPFApplication.CommonInterface" is not a valid namespace identifier.  D:\Dev\WPFApplication\Views\POSViews\SalesScreen.xaml
  </code></pre>
  
  <p>Since I have copied the namespaces from the class model itself, there can not be spelling errors(99%),</p>
  
  <p>Can you give me a help on this to solve the problem fast.</p>
  
  <p>Thanks in advance.</p>