How to bind a datatable to dropdownlist

I have a dropdownlist (my ddl) and I want to bind it to a datatable (myDataTable).   The datatable has two columns departmentNumber and departmentName         

 myddl.DataSource = myDataTable;

 myddl.DataTextField = "departmentName";

 myddl.DataValueField = "departmentNumber";

 myddl.DataBind();