public DateTime?GetDateTime(TRB_KIND kind, TRB_PART part, TRB_PART where, TRB_STATE whereState)
{
DateTime?dt = null;
switch (kind)
{
case TRB_KIND.MINIMUM:
dt = ProjectCollection.Min(proj => proj.GetDateTime(kind, part, where, whereState));
break;
case TRB_KIND.MAXIMUM:
dt = ProjectCollection.Max(proj => proj.GetDateTime(kind, part, where, whereState));
break;
case TRB_KIND.FIRST:
break;
case TRB_KIND.LAST:
break;
default:
break;
}
return(dt);
}