Query list item in external list by object model

SPQuery query = new SPQuery();
var context = SPServiceContext.GetContext(SPSite);
using (var scope = new SPServiceContextScope(context))
{
SPListItemCollection itemcollec = olist2.GetItems(query);
}

Why cannot activate sandbox solution in SharePoint 2010

If you upload a sandbox solution to SharePoint 2010 solution gallery, and would like to activate it, however you find you cannot click the activate button. It's disabled.

Please go to your centeral administrator and click "Service on server" and make sure that your Microsoft SharePoint Fundation SandBox code service has started.