WPF C#: Rearrange items in listbox via drag and drop

Question

I am trying to figure out how to move the items in a pre-populated listbox up and down via mouse drags.

I have looked at the Control.DoDragDrop method from microsoft's api, but I still can't get it to do anything.

I would appreciate any help since I am new to the visual studios environment.

Answer 1

I've tried creating one using ObservableCollection. Have a look.

    ObservableCollection<Emp> _empList = new ObservableCollection<Emp>();      public Window1()     {         InitializeComponent();          _empList .Add(new Emp("1", 22));         _empList .Add(new Emp("2", 18));         _empList .Add(new Emp("3", 29));         _empList .Add(new Emp("4", 9));         _empList .Add(new Emp("5", 29));         _empList .Add(new Emp("6", 9));         listbox1.DisplayMemberPath = "Name";         listbox1.ItemsSource = _empList;                  Style itemContainerStyle = new Style(typeof(ListBoxItem));         itemContainerStyle.Setters.Add(new Setter(ListBoxItem.AllowDropProperty, true));         itemContainerStyle.Setters.Add(new EventSetter(ListBoxItem.PreviewMouseLeftButtonDownEvent, new MouseButtonEventHandler(s_PreviewMouseLeftButtonDown)));         itemContainerStyle.Setters.Add(new EventSetter(ListBoxItem.DropEvent, new DragEventHandler(listbox1_Drop)));         listbox1.ItemContainerStyle = itemContainerStyle;     } 

Drag and drop process:

    void s_PreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e)     {          if (sender is ListBoxItem)         {             ListBoxItem draggedItem = sender as ListBoxItem;             DragDrop.DoDragDrop(draggedItem, draggedItem.DataContext, DragDropEffects.Move);             draggedItem.IsSelected = true;         }     }      void listbox1_Drop(object sender, DragEventArgs e)     {         Emp droppedData = e.Data.GetData(typeof(Emp)) as Emp;         Emp target = ((ListBoxItem)(sender)).DataContext as Emp;          int removedIdx = listbox1.Items.IndexOf(droppedData);         int targetIdx = listbox1.Items.IndexOf(target);          if (removedIdx < targetIdx)         {             _empList.Insert(targetIdx + 1, droppedData);             _empList.RemoveAt(removedIdx);         }         else         {             int remIdx = removedIdx+1;             if (_empList.Count + 1 > remIdx)             {                 _empList.Insert(targetIdx, droppedData);                 _empList.RemoveAt(remIdx);             }         }     } 

Note:

• One thing that sucks in this implementation is that since it uses the PreviewMouseLeftButtonDown event, the dragged item does not look like a selected item.
• And also for an easier implementation, the drop target is the list box items and not the listbox itself - might need a better solution for this.