对CRM中的BusinessEntityCollection进行Linq操作

注意的是要进行CRM数据类型同.NET类型的转换

 1 ColumnSet cs3 = new ColumnSet();
 2 cs3.Attributes = new string[] { "name", "jade_projectdate", "createdon" };
 3 QueryExpression query = new QueryExpression();
 4 query.ColumnSet = cs3;
 5 query.EntityName = EntityName.opportunity.ToString();
 6 BusinessEntityCollection rezult = service.RetrieveMultiple(query);
 7 //opportunity[] opp = (opportunity[])rezult.BusinessEntities;
 8 List<opportunity> opp = new List<opportunity>();
 9 foreach (BusinessEntity project in rezult.BusinessEntities)
 {
     opportunity temp = (opportunity)project;
     opp.Add(temp);
 }
 DateTime test = (from s in opp
          select Convert.ToDateTime(s.createdon.Value)).Max();
 TextBox1.Text =

 另外，还可以使用OrderExpression对Query进行GroupBy

 1             CrmAuthenticationToken token = new CrmAuthenticationToken();
 2             token.AuthenticationType = 0;
 3             token.OrganizationName = "MicrosoftCRM";
 4             CrmService service = new CrmService();
 5             service.Url = "http://localhost:5555/mscrmservices/2007/crmservice.asmx";
 6             service.CrmAuthenticationTokenValue = token;
 7             service.Credentials = System.Net.CredentialCache.DefaultCredentials;
 8             ColumnSet cs = new ColumnSet();
 9             cs.Attributes = new string[] { "jade_start", "jade_status", "jade_activityid" };
             ConditionExpression conExp = new ConditionExpression();
             conExp.Operator = ConditionOperator.EqualUserId;
             conExp.AttributeName = "createdby";
             FilterExpression filExp = new FilterExpression();
             filExp.Conditions = new ConditionExpression[] { conExp };
             OrderExpression odrExp = new OrderExpression();
             odrExp.AttributeName = "jade_start";
             odrExp.OrderType = OrderType.Descending;
             OrderExpression odrExp2 = new OrderExpression();
             odrExp2.AttributeName = "jade_pause";
             odrExp2.OrderType = OrderType.Descending;
             QueryExpression qryExp = new QueryExpression();
             qryExp.ColumnSet = cs;
             qryExp.Criteria = filExp;
             qryExp.EntityName = "jade_timesheetdetail";
             qryExp.Orders = new OrderExpression[] { odrExp, odrExp2 };
             BusinessEntityCollection BEC = service.RetrieveMultiple(qryExp);
             jade_timesheetdetail detail = (jade_timesheetdetail)BEC.BusinessEntities[0];
             if (detail.jade_status.Value == 1)
                 TextBox1.Text =  "test";