using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Volian.Controls.Library
{
    //Class to handle bug in Windows WinForms ListBox
    // that autoselects first item when no items are selected 
    public partial class ListBoxMulti : ListBox
    {
        public ListBoxMulti()
        {
            Visible = true;
            SelectionMode = SelectionMode.MultiSimple;

            SelectedIndexChanged += lb_SelectedIndexChanged;

            Disposed += ListBoxMulti_Disposed;
        }

        //singleselectedindex
        // will help to fix bug in Winforms ListBox
        // that autoselects first item when no items are selected
        // -1 = multi or set to this after 1st initialization
        // if this = 0 and only 1 item selected,
        // that means item was autoselected, so clear all items.
        public int singleselectedindex { get; set; }
        private void lb_SelectedIndexChanged(object sender, EventArgs e)
        {
            ListBoxMulti tmp = (ListBoxMulti)sender;

            if (tmp.SelectedItems.Count == 1 && tmp.singleselectedindex == 0)
            {
                tmp.ClearSelected();
            }
            else if (tmp.SelectedItems.Count == 1)
                tmp.singleselectedindex = tmp.SelectedIndex;
            else
                tmp.singleselectedindex = -1;

        }

        //remove event when get rid of object
        private void ListBoxMulti_Disposed(object sender, EventArgs e)
        {
            SelectedIndexChanged -= lb_SelectedIndexChanged;
        }
    }
}