title: Unable to cast .SelectedItems from DataGrid Issue
body: <p>Alright... it's friday, it's getting late, I'm a little frain bried...</p>
  
  <p>Code:</p>
  
  <pre><code>public partial class SiteSelection : Window
  {
  
      private IList&lt;IISBrowser.IISSiteList&gt; _siteList;
  
      public IList&lt;IISBrowser.IISSiteList&gt; SelectedItemsList { get; set; }
  
      public SiteSelection(IList&lt;IISBrowser.IISSiteList&gt; _sl)
      {
          InitializeComponent();
          _siteList = _sl;
      }
  
      private void Window_Loaded(object sender, RoutedEventArgs e)
      {
          this.dg_Sites.ItemsSource = _siteList;
      }
  
      private void btnSelectSites_Click(object sender, RoutedEventArgs e)
      {
          SelectedItemsList = (IList&lt;IISBrowser.IISSiteList&gt;)dg_Sites.SelectedItems;
          this.Close();
      }
  </code></pre>
  
  <p>Populates a datagrid, where I can select items.  With a button (btnSelectSites)</p>
  
  <p>I keep getting <code>Unable to cast object of type 'System.Windows.Controls.SelectedItemCollection' to type 'System.Collections.Generic.IList 1[Backup.S3.Store.IISBrowser+IISSiteList]'.</code></p>
  
  <p>And do not understand why...  it was my understanding that since I am setting this <code>IList&lt;&gt;</code> when applying to the ItemSource, that I would be returned the same data type..</p>
  
  <p>How can I fix this?</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>Already tried the solution here: <a href="https://stackoverflow.com/questions/14852371/type-list-of-selected-items-in-a-wpf-datagrid">Type list of selected items in a wpf datagrid</a> which is similar to other solutions on here... none of which worked.</p>