I have a situation in which I have a combo box whose values are pulled from a database. Now if I select the first value in the combobox, then it should pull the corresponding values in another combo box.
A more practical view of this would be like this, Imagine I have some questions stored in questions table and the questions will have choices stored in choices table with each choice having the corresponding question id. Now I want to display them in a jsp page in the form of a combo box like I mentioned above. How can I do this? Any help appreciated.
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It is normally called a double combo. You can either do it the classic way of posting back the form onchange of the first dropdown list OR you can look into the nifty Ajax solution. The forum and ranch are full of examples on how to do this.
I tried looking by doing a search, but no satisfactory results I could get. I'm missing out some minute details on the examples spread across over the web. Does anyone here have some links...please I'm in desperate need of it.
GWT supports the notion of RPC calls, which are asynchronous calls to the server. In your GWT code, you invoke the RPC call, passing in a callback class that would get invoked upon completion of the call.
So in your particular case, you would listen for a select event, at which point you invoke the RPC call. Then in the callback handler (where you would have passed back any results from say a db query, etc), you populate your second listbox. All asynchronously, no need to do any post backs or anything. GWT handles all that for you very nicely.