ASP.NET AJAX的Combobox - 无法以编程方式更改所选项

I'm using the new Microsoft ASP.NET Ajax ComboBox control in my web application, and I'm having trouble figuring out how to programmatically set the selected list item. For example, I have a form to accept addresses and a ComboBox to accept a city name. After the user enters and saves and address, I'd like to reset the form, including the ComboBoxes.I'm using the new Microsoft ASP.NET Ajax ComboB