Hi Bernard,
Thanks for contacting Syncfusion Support.
Query: when I select one item, the JS function is not called.
If we enable the checkbox, only the checkChange event will be triggered instead of select/change event in the ListBox control. The select and change events are triggered only when the ListBox is rendered without the checkbox.
Query: When I run the project, checkboxes in the listbox is looking like filled boxes, instead of checkmarks in empty box?
We were unable to reproduce the above issue. When we ran the project, checkmarks in the checkboxes rendered properly in the ListBox control. Please ensure that you have referred dependent scripts and CSS files in your application. For you reference, we have prepared a simple ListBox MVC application with checkbox enabled. You can get that sample from:
If the problem persists still, please modify the provided sample based on your application along with the replication procedure to showcase the issue. Or, you can share the code sample of how you had created the ListBox with checkbox and share the console errors, if any. This would help us to provide an appropriate solution at the earliest.
Regards,
Prasanth P