Question

我正在使用Microsoft CRM 2011网络服务来检索活动列表，但由于数据量的原因，请求已超时。我正在实现分页并尝试进行yield return，但后来我得到了“连接意外关闭”错误。

public IEnumerable<LinkedActivity> GetActivitiesForUser() {
  var svc = GetCrmService();
  var cols = new ColumnSet();
  cols.Attributes = new[] { "activityid", "addressused", "scheduledstart", "scheduledend", "partyid", "activitypartyid", "participationtypemask", "ownerid" };
  var query = new QueryExpression();
  query.EntityName = EntityName.activityparty.ToString();
  query.ColumnSet = cols;

  LinkEntity link = new LinkEntity();
  //link.LinkCriteria = filter;
  link.LinkFromEntityName = EntityName.activitypointer.ToString();
  link.LinkFromAttributeName = "activityid";
  link.LinkToEntityName = EntityName.activityparty.ToString();
  link.LinkToAttributeName = "activityid";
  query.LinkEntities = new[] {link};

  var activities = svc.RetrieveMultiple(query);
  var entities = new List<ICWebServices.activityparty>();
  RetrieveMultipleResponse retrieved = (RetrieveMultipleResponse) svc.Execute(request);
  //var pointers = new List<activitypointer>();
  foreach (activityparty c in activities.BusinessEntities)
  {
      //yield return c; - this returned an error "The connection was unexpectedly closed"
      entities.Add(((activityparty)c));
  }

实现我正在使用的分页：

    var activities = GetActivities();
    var offset = startRowIndex > 0 ? activities.Skip(startRowIndex) : activities;
    var limited = limit > 0 ? offset.Take(limit) : offset.Take(100);
    return limited.ToList();

有什么方法可以退回前100项吗？

Answer 1

您需要在QueryExpression中定义PageInfo

http://msdn.microsoft.com/en-us/library/aa683424.aspx

Answer 2

tyrongower是正确的。此外，您应该将服务包装在using语句中以确保其正确处理。

Answer 3

为什么不在您的应用中使用LINQ和分页？

Linq本身就有这个东西，MS同时拥有REST和SOAP端点。

我没有测试过，但我怀疑REST端点可以直接用于分页。

public static class PagingExtensions
{
//used by LINQ to SQL
public static IQueryable<TSource> Page<TSource>(this IQueryable<TSource> source, int page, int pageSize)
 {
return source.Skip((page - 1)*pageSize).Take(pageSize);
 }

//used by LINQ
public static IEnumerable<TSource> Page<TSource>(this IEnumerable<TSource> source, int page, int pageSize)
 {
return source.Skip((page - 1)*pageSize).Take(pageSize);
 }

}

class Program
{
static void Main(string[] args)
 {
List<string> names = new List<string>();
 names.AddRange(new string[]{"John","Frank","Jeff","George","Bob","Grant", "McLovin"});
foreach (string name in names.Page(2, 2))
 {
Console.WriteLine(name);
 }

 }
}

使用Microsoft CRM限制结果

3 个答案: