Answers

• marcus_helbig Posts: 4Questions: 1Answers: 0

  March 22 edited March 22

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• allan Posts: 61,972Questions: 1Answers: 10,160 Site admin

  March 22

  Can you link to a page showing the issue please? It should be that Scroller will do exactly as you say - wait until the scrolling is near the limit of the data it has before making a request to the server for more data.

  Allan
• marcus_helbig Posts: 4Questions: 1Answers: 0

  March 25

  Hello Allen,

  Thanks for your answer.

  Unfortunately the scroller doesn't do exactly what I expected and as you described. I probably didn't express myself correctly and I'll try again.

  I have a DataTable that displays 48 rows. The DataTable has a length of 400. My server side code connects to a database and determines a total of 1700 valid rows. Of these 1700 lines it returns 400 lines to the DataTable - so far everything is ok.

  What I noticed is different behavior when calling the server side code through the DataTable.

  Version 1:
  If the server side code determines the data very quickly and delivers it to the DataTable, the DataTable calls the server side code as soon as I scroll with the mouse to the lines directly below / the next page (lines 48 - 96). The server side code is called again with start=16 and length=400, even though I have already loaded 400 lines and there are still around 350 lines left for a display.

  Variant 2:
  If I incorporate a sleep of 1000 msec into the server side code, the server side code is not called when scrolling to the lines below (48-96) / next page. Only when I get to line 282 will my server side code with start=32 (why 32?) and length=400 be triggered again.

  I also increased the sleep to 2000 msec. However, the same behavior is seen here as with 1000 msec (variant 2). Then I continuously turned the sleep down. It turns out that the behavior changes with a total running time of the server side function of approx. 700 - 800 msec:
  - Total runtime under 700 to 800 msec: permanent call to the server side code upon click
  - Total running time more than 700 - 800 msec: The server side code is only called when the available lines are displayed - as desired.

  My questions:

  Is there a mechanism within the DataTable that evaluates and uses the speed of the server side code?

  Can I use parameters/options to tell the DataTable when it can call the server side code?

  Here are some code fragments:

  javascript:

  table = $('#myID').DataTable({
  dom: 'tSr',
  processing: true,
  ordering: true,
  order: [[1, "asc"]],
  scrollCollapse: false,
  paging: true,
  serverSide: true,
  ajax: {
  url: "/Controller/Method",
  data: {
  data1: "myData",
  data2: "myData",
  data9: "myData",
  },
  columnDefs: [{ data: "data1", "orderable": true},
  { data: "data2", "orderable": true},
  { data: "data3", "orderable": true}]
  });

  later in code:

  let table = $('#myID').DataTable();
  table.page.len(400);

  server side code C#:

  public object Method(JQueryDataTableParamModel DT-Params)
  {
  /* get data from database */

  /* build json reply */

  System.Threading.Thread.Sleep(1000);

  return Newtonsoft.Json.JsonConvert.SerializeObject(jsonReply);
  }
• allan Posts: 61,972Questions: 1Answers: 10,160 Site admin

  March 25

  Can you give me a link to a page showing the issue please? I've just had a look at this example and it appears to be doing what I would expect.

  Allan
• marcus_helbig Posts: 4Questions: 1Answers: 0

  March 26

  Hi Allen,

  here are two videos:

  This shows the behavior as I expect:
  https://www.youtube.com/shorts/DRcDnxAP7OE

  This shows the permanent call to the server side function:
  https://youtube.com/shorts/cCi07vxjmLU

  Sorry for the poor quality. Video captureing is not possible.