Invalid attempt to read when no data is present. at System.Data.SqlClient.SqlDataReader.CheckDataIsReady(Int32 columnIndex, Boolean allowPartiallyReadColumn, Boolean permitAsync, String methodName) at System.Data.SqlClient.SqlDataReader.TryReadColumn(Int32 i, Boolean setTimeout, Boolean allowPartiallyReadColumn) at System.Data.SqlClient.SqlDataReader.GetValueInternal(Int32 i) at System.Data.SqlClient.SqlDataReader.GetValue(Int32 i) at NFIWWW.kurs.GetHoursForFirstDay(Int32 courseId) in C:\Solution\NFISystem\NFIWWW\kurs.aspx.cs:line 356 at NFIWWW.kurs.ConstructHtmlPresentation(Int32 courseId, DateTime modified, HttpServerUtility server, Byte days, Int32 occasionCount) in C:\Solution\NFISystem\NFIWWW\kurs.aspx.cs:line 304