C#

//Sorted list to hold all controls
SortedList ControlListByTabIndex = new SortedList();
			
//Loop over controls
foreach(Control CurrentControl in this.Controls)
{
    //Add to sortedlist, using the tabindex as the key, and the control itself as the value.
    ControlListByTabIndex.Add(CurrentControl.TabIndex, CurrentControl);
}

//You can now loop over the list, and it is ordered by TabIndex
for (int i = 0 ; i < ControlListByTabIndex.Count ; i++)
  {
    Console.WriteLine(((Control)ControlListByTabIndex.GetByIndex(i)).TabIndex);
    Console.WriteLine(((Control)ControlListByTabIndex.GetByIndex(i)).Name);
}