将成员添加到 CRM 2011 工作流活动中的市场营销列表

我正在尝试将成员添加到 CRM 2011 工作流活动中的市场营销列表中。在执行以下代码后，它表示fromListCreated 成员计数为 0，而它应该是 1。我已经验证members[0]和AddMemberRequest.MemberIds[0]确实包含成员 GUID。有谁知道我错过了什么？

List fromList = new List();
List fromListCreated = new List();
fromList.CreatedFromCode = new OptionSetValue(2);
fromList.ListName = "My List";
Guid fromListGuid = service.Create(fromList);
var list = service.Retrieve("list", fromListGuid, new Microsoft.Xrm.Sdk.Query.ColumnSet(true));
fromListCreated = service.Retrieve(list.LogicalName, list.Id, new Microsoft.Xrm.Sdk.Query.ColumnSet(true)).ToEntity<List>();
Guid emailFrom = Guid.Empty;
if (EmailFrom != null)
{
    emailFrom = EmailFrom.Get(executionContext).Id;
}
else
{
    // Default to the inhouse attorney user
    emailFrom= thisCase.lgl_inhouseattorneyid.Id;
}
Guid[] members = new Guid[1];
members[0] = emailFrom;
AddListMembersListRequest AddMemberRequest = new AddListMembersListRequest();
AddMemberRequest.ListId = fromListCreated.Id;
AddMemberRequest.MemberIds[0] = members[0];
AddListMembersListResponse AddMemberResponse = service.Execute(AddMemberRequest) as AddListMembersListResponse;
service.Update(fromListCreated);