Answers

• colin Posts: 15,240Questions: 1Answers: 2,599

  February 2018

  Hi Mauro,

  I gave this a quick blast here, and as you can see, the events are triggering with this ajax function. Would you be able to provide an example where the problem occurs, please?

  Cheers,

  Colin
• mxmauro Posts: 3Questions: 1Answers: 0

  February 2018

  Hi Colin, found the problem. My code looks like this:

  $('#my_table').DataTable({
      "ajax": function (data, callback, settings) {
          var response = {};
  
          response.recordsTotal = 1;
          response.recordsFiltered = 1;
          response.draw = settings.iDraw;
          response.data = [];
              
          var val = [];
          val[0] = "test data";
          response.data[0] = val;
  
          callback(response);
      }
  }).on('preDraw.dt', function () {
      //do something
  }).on('draw.dt', function () {
      //do something
  });
  

  The problem is DataTable's initialization code renders the "ajax" data before returning so, at that time, preDraw and draw events are not registered. When I redraw the table, events triggers fine.

  Not sure if I should open a GitHub issue or this is an expected behavior (although couldn't find where it is documented)

  Regards,
  Mauro.
• colin Posts: 15,240Questions: 1Answers: 2,599

  February 2018

  Good find. I'm not sure either, I could argue it either way, one @allan methinks.
• allan Posts: 63,534Questions: 1Answers: 10,475 Site admin

  February 2018 Answer ✓

  Its due to the fact that your function is synchronous. Ajax is typically async (the first "A" in the acronym), so normally the events would have been added by the time the Ajax response comes in from the server. But in this case, when you call callback() the events haven't yet been added.

  Adding them before you initialise the table allows them to execute as expected: http://live.datatables.net/razoqevi/1/edit .

  Allan
• mxmauro Posts: 3Questions: 1Answers: 0

  February 2018

  Hi @allan thank you for the tip. It worked! Didn't know one is able to set the "on" events before the initialization.

  Thank you @colin too