Foreach every Subitem in a MenuStrip

Question

I want to get all the SubItems of my MenuStrip, So I can change them all at once.

I'am trying things like the following, but they aren't working:

foreach (ToolStripMenuItem toolItem in menuStrip1.DropDownItems)
{
      //Do something with toolItem here
}

Can someone help me out coding a good foreach loop for getting all the SubMenuItems(DropDownItems) from the MenuStrip?

EDIT now trying to work with the following Recursive method:

private void SetToolStripItems(ToolStripItemCollection dropDownItems)
        {
            try
            {
                foreach (object obj in dropDownItems)
                {
                    if (obj.GetType().Equals(typeof(ToolStripMenuItem)))
                    {
                        ToolStripMenuItem subMenu = (ToolStripMenuItem)obj;

                        if (subMenu.HasDropDownItems)
                        {
                            SetToolStripItems(subMenu.DropDownItems);
                        }
                        else
                        {

                        }
                    }
                }
            }
            catch
            {

            }
        }

Answer 1

Try this:

List<ToolStripMenuItem> allItems = new List<ToolStripMenuItem>();
foreach (ToolStripMenuItem toolItem in menuStrip.Items) 
{
    allItems.Add(toolItem);
    //add sub items
    allItems.AddRange(GetItems(toolItem));
}  
private IEnumerable<ToolStripMenuItem> GetItems(ToolStripMenuItem item) 
{
    foreach (ToolStripMenuItem dropDownItem in item.DropDownItems) 
    {
        if (dropDownItem.HasDropDownItems) 
        {
            foreach (ToolStripMenuItem subItem in GetItems(dropDownItem))
                yield return subItem;
        }
        yield return dropDownItem;
    }
}

Answer 2

Modification of Vale's answer. Separators will not crash this version and they will also be returned ( menuStripItems is a ToolStripItemCollection. ie: this.MainMenuStrip.Items ):

    /// <summary>
    /// Recursively get SubMenu Items. Includes Separators.
    /// </summary>
    /// <param name="item"></param>
    /// <returns></returns>
    private IEnumerable<ToolStripItem> GetItems(ToolStripItem item)
    {
        if (item is ToolStripMenuItem)
        {
            foreach (ToolStripItem tsi in (item as ToolStripMenuItem).DropDownItems)
            {
                if (tsi is ToolStripMenuItem)
                {
                    if ((tsi as ToolStripMenuItem).HasDropDownItems)
                    {
                        foreach (ToolStripItem subItem in GetItems((tsi as ToolStripMenuItem)))
                            yield return subItem;
                    }
                    yield return (tsi as ToolStripMenuItem);
                }
                else if (tsi is ToolStripSeparator)
                {
                    yield return (tsi as ToolStripSeparator);
                }
            }
        }
        else if (item is ToolStripSeparator)
        {
            yield return (item as ToolStripSeparator);
        }
    }

Populate a list:

    List<ToolStripItem> allItems = new List<ToolStripItem>();
    foreach (ToolStripItem toolItem in menuStripItems)
    {
       allItems.Add(toolItem);
       //add sub items
       allItems.AddRange(GetItems(toolItem));
    }

Loop the list:

     foreach(ToolStripItem toolItem in allItems)
     {
          if(toolItem is ToolStripMenuItem)
          { 
             ToolStripMenuItem tsmi = (toolItem as ToolStripMenuItem);
             //Do something with it
          }
          else if(toolItem is ToolStripSeparator)
          {
             ToolStripSeparator tss = (toolItem as ToolStripSeparator);
             //Do something with it
          }
     }