无法理解store.Certificates.Find

Question

var store = new X509Store(StoreName.My);

store.Open(OpenFlags.ReadOnly);

foreach (var mCert in store.Certificates)
{
   Response.Write(store.Certificates.Find(X509FindType.FindBySubjectName, mCert.SubjectName.Name, false).Count + "<br>"); 
}

为什么我有数 - 0作为回应？