This week I came across a very valuable piece of information concerning Coolite combo boxes. A combobox has attribute called Mode. What this is set to greatly affects the overall behavior of the control, and can create extra queries where you may not expect them. I find that having an understanding of this attribute can help you develop more efficient pages using the Coolite ComboBox.
- Default – The default behavior for this control is based on how it initially receives its data. If it is connected to a Store of any kind, it will act according to the rules of Remote if no store is provided it will act according to the rules of Local
- Remote – whenever the dropdown is expanded make a query to the data store to get the latest data and bind the data according to the DisplayField and ValueField. This is where the second query comes in. Even setting AutoLoad to true on the Store will cause this to happen. Be wary of this second query, especially if the query to get the data is heavy, this could easily create a bottleneck
I would assume there is a way to define poll time for the DropDown query, however, I have not explored that, but something I would look at for the later case.
Hope this was helpful, I discovered this and, as usual, found no documentation from Coolite explaining this, so I thought it would be useful to talk about it here.