UserPrincipal.GetGroups仅提取当前域组

Question

我开始使用此代码查找用户所在的所有组：

Using user As UserPrincipal = UserPrincipal.FindByIdentity(domainContext, name)

Dim groupList As AccountManagement.PrincipalSearchResult(Of Principal) = user.GetGroups
    For Each group As GroupPrincipal In groupList
        myUserGroupList.GroupList.Add(group.Name)
    Next
End Using

Return myUserGroupList

我发现这不是从其他域返回组，所以我添加了以下内容：

If domain.ToUpper = "Domain1" Then
    Dim myDomainList As DomainConfiguration.DomainCollection = GetDomains()

    For Each DomainItem As DomainConfigElement In myDomainList
        If DomainItem.DomainName.ToUpper <> "Domain1" Then
            Try
                myUserGroupList.GroupList.Add(DomainItem.DomainName.ToUpper)
                Using OtherDomainContext As New PrincipalContext(ContextType.Domain, DomainItem.DomainName, DomainItem.UserName, DomainItem.Password)
                    myUserGroupList.GroupList.Add("Using: " & DomainItem.DomainName.ToString)
                   Try
                      Dim NewGroupList As AccountManagement.PrincipalSearchResult(Of Principal) = user.GetGroups(OtherDomainContext)
                      myUserGroupList.GroupList.Add(NewGroupList.ToString)
                          If NewGroupList IsNot Nothing Then
                              For Each newgroup As UserPrincipal In NewGroupList
                                  myUserGroupList.GroupList.Add(newgroup.Name)
                              Next
                          Else
                              myUserGroupList.GroupList.Add("No Groups for: " & DomainItem.DomainName.ToString)
                          End If
                   Catch ex As Exception
                      myUserGroupList.GroupList.Add("Other Context Ex: " & ex.ToString)
                   End Try

               End Using

           Catch ex As Exception
               myUserGroupList.GroupList.Add("unable to add: " & DomainItem.DomainName.ToString)
           End Try
       End If

    Next                  
End If

有一点奇怪的是，对于除当前域之外的每个域，我得到myUserGroupList的1个条目，文本为“PrincipalSearchResult`1”。我觉得这应该可行，但我现在已经踢了很长一段时间，微软声称这种行为是By Design。我会尝试任何事情，但我希望避免使用advapi32.dll。感谢任何回答的人。