// Worker for OnAdd and Add(UIElement).
// If returnIndex == true, uses the more costly IList.Add
// to calculate and return the index of the newly inserted
// Run, otherwise returns -1.
private int AddUIElement(UIElement uiElement, bool returnIndex)
{
if (uiElement == null)
{
throw new ArgumentNullException("uiElement");
}
InlineUIContainer implicitInlineUIContainer = Run.CreateImplicitInlineUIContainer(this.Parent);
int index;
if (returnIndex)
{
index = base.OnAdd(implicitInlineUIContainer);
}
else
{
this.Add(implicitInlineUIContainer);
index = -1;
}
implicitInlineUIContainer.Child = uiElement;
return(index);
}
