Exposing other events

By James Goodman on 28 Aug 2017

I'm sure this has been suggested several times and if you wanted a true RAD platform you would implement it. 

Why don't you expose other events like onChange for users to associate an action with.  Like OnFocus, OnBlur, OnKeyPress, OnMouseOver... 

Would that be so hard to do?  

I know there are work arounds, but that takes time and is anything but rapid...



Vasco Pessanha29 Aug 2017

Hi Jim,

Exposing those events as built-in events rather than achieving it through extensibility also has a drawback of making our language (and properties) more complex and harder to understand.

We will take your feedback into account and review how common are these use cases, but take into account that if we promote to much information users will have a hard time to find what is more important.


Vasco Pessanha

Justin James29 Aug 2017

I also think that tying code to those events, where it needs to do a postback to the server, would make for a pretty poor user experience.


Tim Timperman29 Nov 2017

I disagree, J.

Having only the OnChange is far worse a user experience than the OnBlur would be in certain cases. For example, if you want to do a lookup or a quick validation on a value entered in a text field, you'll need the onchange, which triggers a server postback with every single character that you type in that field. If we would have easy access to the onblur, there would only be 1 server postback when the user is finished entering the data, and when it is useful to actually do a lookup or validation.

Justin James29 Nov 2017

Tim -

If you look at the implementation of the OnChange, it actually does NOT trigger a postback with every single character typed. It only does it when they leave the field, or after a little bit (I think 200 ms?) after the user stops changing. As a result, the user experience is pretty decent. Likewise, OnBlur would be fine... but OnKeyPress, OnChange, etc. would be truly miserable to kick off a server postback on each one, unless you were very careful in how it was implemented...


J.30 Nov 2017

I disagree, most of the suggested events are more usefull on clientside, not serverside...

Justin James30 Nov 2017

J -

Sure, so in that case, you don't want the requested change, you want what's already built-in, which is in the "Extended Properties" you see "onfocus", "onblur", etc. and can write JavaScript in there.

Maybe this can be exposed in a more-obvious way, but the ability to do client side JS for those events has been around for a long time.