53 lines
1.6 KiB
C#

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;
}
}
}