title: Clear a combobox in WPF
body: <p>How do I clear a combobox in WPF?  I have tried this code:</p>
  
  <pre><code> private void btClear1_Click(object sender, RoutedEventArgs e)
      {
  
          txtID.Text = String.Empty;
          this.cbType.SelectedItem = -1;
      }
  </code></pre>