title: WPF change datagrid combobox ItemsSource to value of another datagrid combox
body: <p>I have a datagrid with 2 DataGridComboxClolumn elements and want to change the ItemsSource of the second when the value of the first is changed. How can I set up such a binding?</p>
  
  <p>Note: the datagrid has it's own itemssource and the data is hierachical following:</p>
  
  <p>ItemsSource of the datagrid (list op type Channel):</p>
  
  <pre><code>public class Root
  {
      public List&lt;Channel&gt; Ch { get; set; }  // This is the ItemsSource of the datagrid itself
  }
  
  
  public class Channel
  {
      public Settings TheSettings { get; set; }
  }
  </code></pre>
  
  <p>The thing I want to accomplish is that the TheSettings is set with selected value of the second ComboBox. This is easyly done by setting the ComboBox ItemsSource. Although I require that the ItemsSource of the second combox to be dynamic. E.g. it has to change to the source selected in the FIRST combobox. How can this be done?</p>