stdrc

// Create a subclass of `UITextField` or `UITextView`,
// and override the `canPerformAction:withSender:` method like following:
 
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
    if (action == @selector(copy:))
        return NO;
    return [super canPerformAction:action withSender:sender];
}