在应用程序中可以通过ipersiststream接口来加载一个graphedit (.grf) file，实例代码如下
hresult loadgraphfile(igraphbuilder *pgraph, const wchar* wszname)
{
istorage *pstorage = 0;
if (s_ok != stgisstoragefile(wszname))
{
return e_fail;
}
hresult hr = stgopenstorage(wszname, 0,
stgm_transacted | stgm_read | stgm_share_deny_write,
0, 0, &pstorage);
if (failed(hr))
{
return hr;
}
ipersiststream *ppersiststream = 0;
hr = pgraph->queryinterface(iid_ipersiststream,
reinterpret_cast<void**>(&ppersiststream));
if (succeeded(hr))
{
