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 108:                        aanraders = aanraders.Union(templijst).Distinct.ToList
Line 109:
Line 110:                        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 111:                        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 112:                    End If

Source File: D:\inetpub\wwwroot\cnosite\components\cno_opleidingen\cno_opleidingen.ascx.vb    Line: 110

Stack Trace:


[InvalidOperationException: Sequence contains no elements]
   System.Linq.Enumerable.First(IEnumerable`1 source) +417
   components_cno_filters_cno_opleidingen.filterNascholingen() in D:\inetpub\wwwroot\cnosite\components\cno_opleidingen\cno_opleidingen.ascx.vb:110
   components_cno_filters_cno_opleidingen.Page_Load(Object sender, EventArgs e) in D:\inetpub\wwwroot\cnosite\components\cno_opleidingen\cno_opleidingen.ascx.vb:13
   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