custom validator against remote object

Question

I have a need to validate a field against our database to verify unique-ness. The problem I seem to be having is that the validators doValidation() exits before we've heard back from database.

How can I have the validator wait to return its payload until after we've heard from the DB?

Or perhaps a better question might be (since I think the first question is impossible), how can I set this up differently, so that I don't need to wait, or so that the wait doesn't cause the validation to automaticallly return valid?

Answer 1

If you're using a remote object, you can specify the method call inside your remote declaration and assign a function to the result call. The result call only runs once the remote server returns something, so it won't be run before your validation.

Do your validation call in said result function call (which you will have to create) and you should be good. Your code should go something like this:

<s:RemoteObject id="employeeService"
  destination="ColdFusion"
  source="f4iaw100.remoteData.employeeData"
  endpoint="http://adobetes.com/flex2gateway/"
  result="employeeService_resultHandler(event)"/>
    **<s:method name="dataCheckCall" result="dataCheckResult(event)"/>**
<s:RemoteObject />

And in your script:

function protected dataCheckResult(event:ResultEvent):void {
  **doValidate();**
}

Edit: As soon as you call "dataCheckCall" the method will start running. If, for whatever reason, you want to call this WITHIN your validator, you can do so, and then dataCheckResult will run whenever it returns with it's payload (pretend doValidate is called elsewhere). I've left a message below as well.

Answer 2

You are trying to fit an asynchronous process (fetching data from a DB) into a synchronous process (checking all the validators in turn).

This won't work...

You'll need to either roll your own validator framework, or use a different method of determining the legality of your controls.

P.S. The MX validators are rubbish anyway!

Answer 3

What I've managed to do, seems to work, mostly. I don't like it, but it at least performs the validation against the remote source.

What I've done, then, is to use an 'keyUp' event handler to spin off the database lookup portion. In the meanwhile, I set up a string variable to act as some kind of a Flag, which'll be marked as 'processing'. When the response event fires, I'll examine its contents, and either clear the flag, or set it to some kind of other error.

Then, I have created a new 'EmptyStringValidator' will check the contents of this flag, and do its job accordingly.

Its indirect, but, so far, seems to work.