问如何在C#中从outlook中获取EmailId

EN

    public string GetEmaiId(string userId)
    {
        string email = string.Empty;
        DirectorySearcher objsearch = new DirectorySearcher();
        string strrootdse = objsearch.SearchRoot.Path;
        DirectoryEntry objdirentry = new DirectoryEntry(strrootdse);
        objsearch.Filter = "(& (cn=" + userId + ")(objectClass=user))";
        objsearch.SearchScope = System.DirectoryServices.SearchScope.Subtree;
        objsearch.PropertiesToLoad.Add("cn");
        objsearch.PropertyNamesOnly = true;
        objsearch.Sort.Direction = System.DirectoryServices.SortDirection.Ascending;
        objsearch.Sort.PropertyName = "cn";
        SearchResultCollection colresults = objsearch.FindAll();
        foreach (SearchResult objresult in colresults)
        {
            email = objresult.GetDirectoryEntry().Properties["mail"].Value.ToString();
        }
        objsearch.Dispose();
        return email;
    }