Listbox should not be empty

Posted by: nivishapanwar on 22 February 2021, 5:12 pm EST

  • Posted 22 February 2021, 5:12 pm EST

    Hello,
    I am using a wijmo listbox . In that I am using add, remove , update functions.
    How can i restrict the listbox to be not empty, means there should be always a record present in listbox.
    removeRecord() {
    let lb = this.ListData.collectionView;
    lb.items.splice(this.ListData.selectedIndex, 1);
    lb.refresh();
    this.ListData.selectedIndex = -1;
    this.fullname = "";
    this.saveListBoxData();
    }
    displayListBoxValueInTextField(listBox) {
    this.fullname = listBox.selectedValue;
    }
    Thank you.

    Regards,
    Nivisha Panwar
  • Replied 22 February 2021, 9:51 pm EST

    Hi Nivisha,

    You can add a check initially whether at least one item is present or not:
    removeRecord() {
    let lb = this.ListData.collectionView;
    if(lb.totalItemCount <= 1) {
    return;
    }
    .....
    }

    Regards,
    Ashwin
  • Replied 28 February 2021, 10:31 pm EST

    Hi Ashwin,
    I tried using this, but it gave an error that totalitemcount property doesn't exist in collection view.
    Then I tried with ._src.length but still got the same error.Can you suggest something else?
    Thank you.

    Regards,
    Nivisha
  • Marked as Answer

    Replied 1 March 2021, 10:55 pm EST

    Hi Nivisha,

    This type of error is not thrown by JS. If the totalItemCount property is not present in CollectionView, then it will return undefined and will not produce this error. So, please make sure that this.ListData.collectionView is actually an instance of CollectionView.
    You can also use items.length or sourceCollection.length property.

    ~regards
  • Replied 1 March 2021, 11:03 pm EST

    Hi Ashwin,

    Thanks for the help, sourceCollection.length property worked.

    Regards,
    Nivisha

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