How to change the datasource without triggering the change event

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Lee
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Lee asked on 18 Jul 2023, 08:57 PM | edited on 20 Jul 2023, 01:07 PM

I have a kendo dropdown tree and when I set the datasource after initialization via .setDataSource([...]) it triggers the change event. How do I prevent this from happening? I am setting the datasource with a local javascript array of objects. I saw in another forum post to set the value to an empty array. I tried that but it still triggered the on change event. I'm doing this because I have 2 dropdowntrees (one in a flyout panel and one in the header) that I need to keep in sync.

Here is a dojo demonstrating my issue
https://dojo.telerik.com/iKoBOVIk/30

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Nikolay
Telerik team
answered on 21 Jul 2023, 12:55 PM

Hello Lee,

You can unbind the change event before calling the setDataSource() method and bind it back after it finishes:

    $("#test").click(function(){
      dropdowntree.value(""); //clear the dropdown list
      dropdowntree.unbind("change");
      dropdowntree.setDataSource(test_dataSource2);
      dropdowntree.bind("change");
      dropdowntree.value(4);
     })

Dojo demo: https://dojo.telerik.com/iKoBOVIk/33

Regards,
Nikolay
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Lee
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commented on 21 Jul 2023, 02:40 PM | edited

This partially works but if you look in the console you'll notice it still logs "2 changed". The weird thing is that 2 is never actually touched. 

I feel like this is a bug in Kendo UI.

Nikolay
Telerik team
commented on 26 Jul 2023, 08:17 AM

Hi Lee,

You should not pass to the setDataSource() a reference of an existing data source of another ListView but rather create a new data source:

let test_dataSource2 = new kendo.data.HierarchicalDataSource({
        data: test_dataSource
      })

      // clear dropdown values on button click
      $("#test").click(function(){
        dropdowntree.value(""); //clear the dropdown list
        dropdowntree.setDataSource(test_dataSource2);
        dropdowntree.value(4);
        dropdowntree.trigger("change");
      })

Dojo demo: https://dojo.telerik.com/uSEnOdOp

Regards,

Nikolay

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