Display a drop-down list with custom UI. The C1DropDown control makes it easy to customize your dropdown control for WPF.
With DropDown, you have complete control over creating specialized drop-down editors. Attach your logic to the spin buttons and your own drop-down form/editor to the drop-down button. For example, you could place a DataGrid in the drop-down portion and code its row selection event to display a value from that row in the header portion.
You can explicitly set the width and height of the drop-down or have it sized automatically to fit the content.
Configure the WPF drop-down box to display above or below the header portion, or set the direction preference the control will use if there is enough space available on the form.