How do I get listbox items when added by end user

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C#

ListBox

I am using drag and drop functionality by devexpress to fill a listbox by dragging items from a data grid

the problem is not related to devexpress or dragging and dropping, it works just fine but the listbox.Items.Count is always 0 even if the listbox contains items

I've been looking for a solution and the best guess is that the listbox filled by end-user will always be empty in code for some reason.

is there a way to actually get the listbox.items and manipulate them in code for this scenario

Edit/

it's in wpf. I just added a list box with the drag and drop functionality and a button that retrieves the number of items in the listbox (listbox.Items.count.ToString()). in the beinning the listbox is empty and when the end-user adds items to the listbox and clicks the button it should return the number of items they added. instead t always returns 0. Maybe the added items (by the end user) are not counted

What I have tried:

private void OnDrop(object sender, DevExpress.Xpf.Core.DropRecordEventArgs e)
        {
            
            if (e.Data.GetDataPresent(typeof(RecordDragDropData)))
             {
                var data = (RecordDragDropData)e.Data.GetData(typeof(RecordDragDropData));
                var newRecords = data.Records.OfType<Person>().Select(x => new Employee(XpoDefault.Session) { EmpName= x.PerName}).ToArray();
                if (newRecords.Length > 0)
                {
                    DataObject dataObject = new DataObject();
                    dataObject.SetData(new RecordDragDropData(newRecords));
                    e.Data = dataObject;

                }

            }
        }