Limit Results With Microsoft CRM

I'm using Microsoft CRM 2011 web services to retrieve a list of activities but the request is timing out due to the amount of data. I'm implementing paging and tried doing yield return, but then I got an 'The connection was unexpectedly closed' error.

public IEnumerable<Linked开发者_JAVA技巧Activity> 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));
  }

To implement paging I'm using:

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

Is there any way I can just return the first 100 items?

You need to define a PageInfo your QueryExpression

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

tyrongower is correct. Also, you should wrap your service in a using statement to ensure its properly disposed of.

Why not use LINQ, and paging in your app?

Linq has this stuff natively, and MS has both REST and SOAP endpoints.

I have not tested, but I suscpect that the REST endpoint can be used directly with paging.

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);
 }

 }
}