private static void HandleSelectAll(ItemCheckEventArgs e, ToolStripCheckedListBox checkedList, int selectAllIndex)
{
if (e.Index == selectAllIndex)
{
if (e.NewValue == CheckState.Checked)
{
checkedList.CheckAll();
}
if (e.NewValue == CheckState.Unchecked)
{
checkedList.UncheckAll();
}
return;
}
var count = checkedList.CheckedItems.Count;
if (checkedList.GetItemCheckState(selectAllIndex) != CheckState.Unchecked)
{
count--;
}
if (e.NewValue != e.CurrentValue)
{
if (e.NewValue == CheckState.Checked)
{
count++;
}
else
{
count--;
}
}
if (count == 0)
{
checkedList.SetItemState(selectAllIndex, CheckState.Unchecked);
}
else if (count == checkedList.Items.Count - 1)
{
checkedList.SetItemState(selectAllIndex, CheckState.Checked);
}
else
{
checkedList.SetItemState(selectAllIndex, CheckState.Indeterminate);
}
}
