Performance: On demand mode for dropdown list boxes
When analyzing traces in Web UI you may see expensive calls of V Getter methods. Often the reason is an expensive logic
to determine the content of a dropdown list box. See screen shot below for a real world example. In this case the runtime to populate the listbox is 300 milliseconds. If the logic is expensive and for example involves an authority check, it could be even much worse.
Now the content of a dropdown list box really only needs to be known when the user clicks on it. Therefore the Web UI framework provides a functionality, which is not widely known, to read the dropdown values to this point so that not each roundtrip suffers from the increased runtime.
The functionality and how to implement it is described in below consulting note.