Server Error in '/' Application.

Sequence contains no elements

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: Sequence contains no elements

Source Error:


Line 296:                        aanraders = aanraders.Union(templijst).Distinct.ToList
Line 297:
Line 298:                        litTitle.Text = db.tblRichtingCategorie.Where(Function(c) c.categorieID = catID).First.naam '& " -> " & db.tblRichting.Where(Function(c) c.richtingID = onderwijsstructuur).First.naam & " -> " & db.tblInteresses.Where(Function(c) c.interesseID = mainInteresseCode).First.naam
Line 299:                        litWerkgroep.Text = db.tblRichtingCategorie.Where(Function(c) c.categorieID = catID).First.naam & " / " & db.tblRichting.Where(Function(c) c.richtingID = onderwijsstructuur).First.naam & " / " & db.tblInteresses.Where(Function(c) c.interesseID = mainInteresseCode).First.naam
Line 300:                    End If

Source File: D:\inetpub\wwwroot\cnosite\components\cno_opleidingen\cno_opleidingen.ascx.vb    Line: 298

Stack Trace:


[InvalidOperationException: Sequence contains no elements]
   System.Linq.Enumerable.First(IEnumerable`1 source) +417
   components_cno_filters_cno_opleidingen.filterInterne() in D:\inetpub\wwwroot\cnosite\components\cno_opleidingen\cno_opleidingen.ascx.vb:298
   components_cno_filters_cno_opleidingen.Page_Load(Object sender, EventArgs e) in D:\inetpub\wwwroot\cnosite\components\cno_opleidingen\cno_opleidingen.ascx.vb:11
   System.Web.UI.Control.OnLoad(EventArgs e) +108
   System.Web.UI.Control.LoadRecursive() +90
   System.Web.UI.Control.LoadRecursive() +185
   System.Web.UI.Control.LoadRecursive() +185
   System.Web.UI.Control.LoadRecursive() +185
   System.Web.UI.Control.LoadRecursive() +185
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1533


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4494.0