I have the following YSOD. At first it seems a simple thing to solve, except that it doesn't actually appear to be my code. It is in a render method, except we shouldn't be at this particular point in the page lifecycle (so what is it rendering?). If it is my code that's causing the problem I cannot see where it is coming from.
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
[NullReferenceException: Object reference not set to an instance of an object.] Infragistics.WebUI.WebSchedule.MultiResourceViewCaption.RenderButton(HtmlTextWriter writer, Resource resource) +472 Infragistics.WebUI.WebSchedule.MultiResourceViewCaption.Render(HtmlTextWriter writer) +784 Infragistics.WebUI.WebSchedule.WebMonthViewFrame.Render(HtmlTextWriter sink) +1152 Infragistics.WebUI.WebSchedule.WebMonthViewRenderer.RenderContents(HtmlTextWriter writer) +2567 Infragistics.WebUI.WebSchedule.WebMonthView.RenderContents(HtmlTextWriter writer) +152 Infragistics.WebUI.WebControls.SmartWebControl.Render(HtmlTextWriter output) +133 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Control.Render(HtmlTextWriter writer) +10 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Control.Render(HtmlTextWriter writer) +10 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Control.Render(HtmlTextWriter writer) +10 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +173 System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +31 System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +53 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +40 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Control.Render(HtmlTextWriter writer) +10 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Control.Render(HtmlTextWriter writer) +10 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +208 System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +8 System.Web.UI.Page.Render(HtmlTextWriter writer) +29 System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27 System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +100 System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3060
Here's some info I discovered that may prove valuable to yourself or others...
For whatever reason, our prototype was only returning one resource. Once we populated our WebScheduleInfo control with multiple resources, then things started working.
While WebScheduleDbProvider.WebScheduleInfo.VisibleResources.Count = 1, the exception occurs.
While WebScheduleDbProvider.WebScheduleInfo.VisibleResources.Count > 1, the exception does not occur.
Sorry - We still didn't find out what went wrong. So far we've not re-encountered this problem.
It looks like you're not the only one to experience the problem. We are trying to solve the same problem here.
I will go through the process of narrowing the scope of the search like you did.
Did you ever find out what caused the problem?
I still don't know what caused this so I rolled back my souce code to the last version I knew worked and then slowly re-added in all the chages I made testing at each step to see where it broke. It didn't.
I have no idea what caused this, but it seems to work now.