如何序列化Microsoft.SharePoint.Client.ListItem (Sharepoint-2013)？

Question

我希望创建一个返回SharePoint ListCollection的WCF服务。我通过使用以下代码进行了尝试：

public class Service1 : IService1
{
    public ListItemCollection GetList()
    {
        string username = "xxx";
        string userPassword ="xxx";
        var securePassword = new SecureString();
        for (int i = 0; i < userPassword.Length; i++)
        {
            securePassword.AppendChar(userPassword[i]);
        }
        var creds = new SharePointOnlineCredentials(username, securePassword);
        var clientContext = new ClientContext("MySharepointurl");
        clientContext.Credentials = creds;

        List announcementsList = clientContext.Web.Lists.GetByTitle("mylist");
        CamlQuery query = CamlQuery.CreateAllItemsQuery(100);
        var items = announcementsList.GetItems(query);
        clientContext.Load(items);
        clientContext.ExecuteQuery();

        return items;

    }

}

但它给我的错误如下：

不能序列化“Microsoft.SharePoint.Client.ListItem”类型。考虑用DataContractAttribute属性标记它，并用DataMemberAttribute属性对它的所有成员进行标记。如果类型是集合，请考虑使用CollectionDataContractAttribute标记它。有关其他受支持类型，请参阅文档。

Answer 1

在搜索了很多之后，我发现了我的解决方案如下，如果有人有同样的问题：

public List<MyClass> GetList()
    {
        try
        {
            string username = ConfigurationManager.AppSettings["username"];
            string password = ConfigurationManager.AppSettings["password"];
            string url = ConfigurationManager.AppSettings["AccountUrl"];
            var newList = new List<MyClass>();
            var securePassword = new SecureString();
            for (int i = 0; i < password.Length; i++)
            {
                securePassword.AppendChar(password[i]);
            }
            var creds = new SharePointOnlineCredentials(username, securePassword);
            var clientContext = new ClientContext(url)
            {
                Credentials = creds
            };

            List announcementsList = clientContext.Web.Lists.GetByTitle("mylist");
            CamlQuery query = CamlQuery.CreateAllItemsQuery();
            var items = announcementsList.GetItems(query);
            clientContext.Load(items);
            clientContext.ExecuteQuery();
            foreach (var col in items)
            {
                newList.Add(new MyClass()
                {
                    Id = Convert.ToInt32(col["ID"]),
                    FirstName = (string) col["FN"],
                    LastName = (string) col["LN"],
                    Email = (string) col["EM"],
                    UserId = (string) col["UID"],
                    Password = (string) col["PD"],
                    Title = (string) col["Title"]
                });
            }
            return newList;
        }
        catch (Exception)
        {
            return null;
        }

    }