title: How to create ComboBox like UserControl in WPF
body: <p>I'm trying to build an usercontrol wich is able to take elements from XAML like this:</p>
  
  <pre><code>            &lt;ComboBox &gt;
                  &lt;ComboBoxItem /&gt;
                  &lt;ComboBoxItem /&gt;
                  &lt;ComboBoxItem /&gt;
              &lt;/ComboBox&gt;
  </code></pre>
  
  <p>In the <code>ComboBox</code>, you can just add the Items between the <code>ComboBox</code> tags, and I would like to copy this, but I don't know where to start.</p>
  
  <p>Finished it should look like this:</p>
  
  <pre><code>    &lt;cis:ReportControl Grid.Row="3"&gt;
              &lt;cis:ReportItem /&gt;
      &lt;/cis:ReportControl&gt;
  </code></pre>
  
  <p>In the <code>cis:ReportControl</code>, there are some <code>Button</code>s and a <code>ComboBox</code>, and basically I only want to feed the <code>ComboBox</code> with Items. </p>
  
  <p>The Report Item is just a <code>ComboBoxItem</code> with some extra properties.</p>
  
  <p><strong>Edit:</strong></p>
  
  <p>I've implemented it according to @Snowbears answer, but the problem now is that the control has itself as an item. 
  I think this is because I have some content, and by defining the <code>ContentProperty</code> to my <code>ComboBox</code>, it is redirected into the Box.
  What can I do to avoid this?</p>
  
  <p><strong>Edit II:</strong> </p>
  
  <p>It fully works now with this: </p>
  
  <pre><code>    private ItemCollection reportItems;
      public ItemCollection ReportItems
      {
          get
          {
              if (reportItems == null)
              {
                  reportItems = this.ComboBoxReports.Items;
              }
              return reportItems;
          }
      }
  </code></pre>
  
  <p>with the <code>[ContentProperty("ReportItems")]</code> Attribute. ComboBoxReports is the ComboBox in the Control, and I had to inherit from <code>ItemsControl</code> to get it to work.</p>