We're using RadScheduler for scheduling, which allows users to move around scheduled services. However, occasionally, we receive this error.
System.ArgumentOutOfRangeException: Insertion index was out of range. Must be non-negative and less than or equal to size. Parameter name: index
at System.Web.UI.StateManagedCollection.System.Collections.IList.set_Item(Int32 index, Object value)
at Telerik.Web.StronglyTypedStateManagedCollection`1.set_Item(Int32 index, ItemType value)
at Telerik.Web.UI.RadScheduler.Telerik.Web.UI.IScheduler.HandleMove(Appointment appointmentToMove, DateTime start, DateTime end, Boolean editSeries, ResourceUpdateInfo resourceUpdateInfo)
at Telerik.Web.UI.Scheduler.Views.Week.GroupedByResource.Model.HandleMove(Appointment appointment, ISchedulerTimeSlot sourceSlot, ISchedulerTimeSlot targetSlot, Boolean editSeries)
at Telerik.Web.UI.Scheduler.Views.SchedulerModel.ProcessPostBackCommand(SchedulerPostBackEvent postBack)
at Telerik.Web.UI.RadScheduler.ProcessPostBackCommand(SchedulerPostBackEvent postBack)
at Telerik.Web.UI.RadScheduler.RaisePostBackEvent(String eventArgument)
at Telerik.Web.UI.RadScheduler.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument)
at System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument)
at System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
It's been going on for years, and we don't have a clue how it happens. We have not been able to replicate it. I'm wondering if somebody could give us a clue how it might happen from the error message.
Thank you.