void ISubmitInterceptorLink.InvokeNext(SubmitInterceptor current, SubmitArgs e)
{
//不需要检查 Index。
//因为作为最后一个 Submitter(DataProvider)，不能再调用 GetNext 方法。
var next = _submitters[current.SubmitInterceptorIndex - 1];
next.Submit(e, this);
}
internal void Add(SubmitInterceptor submitterInterceptor)
{
if (submitterInterceptor == null)
{
throw new ArgumentNullException("submitterInterceptor");
}
_submitters.Add(submitterInterceptor);
submitterInterceptor.SubmitInterceptorIndex = _submitters.Count - 1;
}