OData 服务未返回完整响应

Question

我正在使用 Odata RESTful 服务阅读 Sharepoint 列表数据（>20000 个条目），详细信息请参见此处 -http://blogs.msdn.com/b/ericwhite/archive/2010/12/09/getting-started-using-the- odata-rest-api-to-query-a-sharepoint-list.aspx

我能够读取数据，但只获取前 1000 条记录。我还检查了 sharepoint 服务器上的列表视图限制是否设置为 5000。请指教。

更新：

@Turker：你的答案很正确！非常感谢。我在第一次迭代中获得了前 2000 条记录。但是，我在 while 循环的每次迭代中都得到相同的记录。我的代码如下-

                         ...initial code...
                     int skipCount =0;
  while (((QueryOperationResponse)query).GetContinuation() != null)
                {
                    //query for the next partial set of customers
                    query = dc.Execute<CATrackingItem>(
                        ((QueryOperationResponse)query).GetContinuation().NextLinkUri
                        );

                    //Add the next set of customers to the full list
                    caList.AddRange(query.ToList());

                    var results = from d in caList.Skip(skipCount)
                                  select new
                                  {
                                      Actionable = Actionable,
                                    };  Created = d.Created,

                        foreach (var res in results)
                        {

                            structListColumns.Actionable = res.Actionable;
                            structListColumns.Created= res.Created;
                        }
                         skipCount = caList.Count;
                     }//Close of while loop

Answer 1

您是否在 Feed 末尾看到 元素？

例如，如果您查看

http://services.odata.org/Northwind/Northwind .svc/Customers/

看到

<link rel="next" href="http://services.odata.org/Northwind/Northwind.svc/Customers/?$skiptoken='ERNSH'" />

您将在提要末尾

http://services.odata.org/Northwind/Northwind.svc/Customers/?$skiptoken='ERNSH' 

，这意味着该服务正在实现服务器端分页，您需要发送查询才能获取下一组结果。

Answer 2

我没有发现你的代码有什么特别的错误。您可以尝试转储请求的 URL（从代码中或使用 fiddler 之类的东西）以查看客户端是否确实发送相同的查询（从而获得相同的响应）。

无论如何，这里是一个可以工作的示例代码（使用示例服务）：

DataServiceContext ctx = new DataServiceContext(new Uri("http://services.odata.org/Northwind/Northwind.svc"));

QueryOperationResponse<Customer> response = (QueryOperationResponse<Customer>)ctx.CreateQuery<Customer>("Customers").Execute();
do
{
    foreach (Customer c in response)
    {
        Console.WriteLine(c.CustomerID);
    }

    DataServiceQueryContinuation<Customer> continuation = response.GetContinuation();
    if (continuation != null)
    {
        response = ctx.Execute(continuation);
    }
    else
    {
        response = null;
    }
} while (response != null);

Answer 3

我遇到了同样的问题，并希望它成为一个通用的解决方案。
因此，我使用 GetAlltems 方法扩展了 DataServiceContext。

    public static List<T> GetAlltems<T>(this DataServiceContext context)
    {
        return context.GetAlltems<T>(null);
    }

    public static List<T> GetAlltems<T>(this DataServiceContext context, IQueryable<T> queryable)
    {
        List<T> allItems = new List<T>();
        DataServiceQueryContinuation<T> token = null;

        EntitySetAttribute attr = (EntitySetAttribute)typeof(T).GetCustomAttributes(typeof(EntitySetAttribute), false).First();

        // Execute the query for all customers and get the response object.
        DataServiceQuery<T> query = null;

        if (queryable == null)
        {
            query = context.CreateQuery<T>(attr.EntitySet);
        }
        else
        {
            query = (DataServiceQuery<T>) queryable;
        }

        QueryOperationResponse<T> response = query.Execute() as QueryOperationResponse<T>;

        // With a paged response from the service, use a do...while loop 
        // to enumerate the results before getting the next link.
        do
        {
            // If nextLink is not null, then there is a new page to load.
            if (token != null)
            {
                // Load the new page from the next link URI.
                response = context.Execute<T>(token);
            }

            allItems.AddRange(response);
        }
        // Get the next link, and continue while there is a next link.
        while ((token = response.GetContinuation()) != null);

        return allItems;
    }