Getting a JavaScript variable value from ajax callback?

[nlights]

I want to evaluate some condition in Javascript using an XBasic ajax callback function, and then have Javascript take action based on the value that was calculated in the XBasic code.

Let's say I have some javascript code, such as:

var testvar='1';
{grid.Object}.ajaxCallback('G','{Grid.RowNumber}:all','isRowLocked','','');
alert(testvar);

The isRowLocked XBasic function returns something like this:

isRowLocked = "testvar = '2';"

However, back in my Javascript, after the ajax call, alert(testvar) still echoes back '1' rather than '2'.

What am I missing here? I assume it has to do with variable scoping or the asynchronous callback somehow, and if so, how can I change a javascript var value in the XBasic return JS code, or is it even possible? Do I have to use a session variable for this? What would that code look like? If this is not possible, how could I go about doing this?

Thank you for any ideas you might have.

Thanks!

[nlights]

Re: Getting a JavaScript variable value from ajax callback?

Found the answer in video D66.

[nlights]

Re: Getting a JavaScript variable value from ajax callback?

I'll take it back: NO, the answer in video D66 works ONLY in dialogs, not in grids, contrary to what the video states multiple times. I was able to replicate the video setup on dialogs where everything works as advertised, but this approach simply does not work on grids.

What I'm trying to do is this:
JS: initialize a state variable X='N/A'
run AjaxCallBack
XB: set state variable X='Yes' or 'No'
JS: see what state variable X contains (should not be 'N/A' any more)

I've tried all kinds of tricks with {grid.object}.setStateInfo() and getStateInfo() but to no avail. XBasic can't seem to change the value of X, even if it returns a properly formatted setStateInfo() -JS command.

Any ideas?

[madtowng]

Re: Getting a JavaScript variable value from ajax callback?

In your xbasic function, assuming you are using e,
try e._state.testvar = "2"

[agillbb]

Re: Getting a JavaScript variable value from ajax callback?

Pertti,
You are forgetting that AJAX calls are Asynchronous. You should probably google what AJAX is all about to get a full understanding.
Thus, any js that immediately follows your initial callback call will be processed IMMEDIATELY, and therefore long before the js code is returned from the callback.
Therefore, you should return all js code from within the callback itself.
e.g.
isRowLocked = "var testvar = '2'; alert(testvar);"

[nlights]

Re: Getting a JavaScript variable value from ajax callback?

Andy,

That's true, having worked so long with systems that maintain state, it is easy to forget how ajax operates. Thanks for the reminder and the code snippet.

[madtowng]

Re: Getting a JavaScript variable value from ajax callback?

My testing shows the state variable being changed in the xbasic function,
but I can't find the way to access the state variable via javascript.
I have 1 button to set the state variable via xbasic, and a seperate button
to display the state variable via javascript, but I keep getting an alert that
says the state variable is undefined.

[danh]

Re: Getting a JavaScript variable value from ajax callback?

You can read and write e._state objects in xbasic and javascript like this:

set in xbasic:
e._state.testvar = "myvalue"

read in javascript:
var v1 = {dialog.Object}.stateInfo.testvar;
alert('testvar value: ' + v1);

Or visa versa - set in javascript:
{dialog.Object}.stateInfo.testvar = 'myvalue';

read in xbasic:
dim testvar as c = e._state.testvar

So, e._state in xbasic becomes {grid/dialog.Object}.stateInfo in javascript.
Haven't used it in the grid, (that I remember) but I think it works the same way.

[nlights]

Re: Getting a JavaScript variable value from ajax callback?

Thank you for your response. As also shown in video D66, it works well with dialogs. Based on my own testing, this approach doesn't work at all with grids. Would be nice if it did, though, because I often run into situations where I need to see and change a certain variable value in both client and server.