Faster WPF ComboBoxes

If you create a WPF ComboBox with 2000 items it will take about 2 seconds to drop down, and about 1 second to retract back. But you can make all operations complete instantly if the items are simple (such as strings). If you are writing XAML, add:

<ComboBox>
  <ComboBox.ItemsPanel>
    <ItemsPanelTemplate>
      <VirtualizingStackPanel />
    </ItemsPanelTemplate>
  </ComboBox.ItemsPanel>

  ...
</ComboBox>

If you are writing C#, add:

comboBox.ItemsPanel = new ItemsPanelTemplate(new FrameworkElementFactory(typeof(VirtualizingStackPanel)));

Thanks to Henry Hahn for the XAML code I started from. Reading the C# version, I am reminded of the Hammer Factory joke.