Server Error in '/' Application.

Object reference not set to an instance of an object.

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.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

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.

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
   System.Data.Linq.SqlClient.QueryConverter.VisitInvocation(InvocationExpression invoke) +504
   System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +1467
   System.Data.Linq.SqlClient.QueryConverter.VisitExpression(Expression exp) +31
   System.Data.Linq.SqlClient.QueryConverter.VisitBinary(BinaryExpression b) +37
   System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +520
   System.Data.Linq.SqlClient.QueryConverter.VisitExpression(Expression exp) +31
   System.Data.Linq.SqlClient.QueryConverter.VisitBinary(BinaryExpression b) +23
   System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +520
   System.Data.Linq.SqlClient.QueryConverter.VisitExpression(Expression exp) +31
   System.Data.Linq.SqlClient.QueryConverter.VisitWhere(Expression sequence, LambdaExpression predicate) +134
   System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc) +4785
   System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc) +71
   System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +1114
   System.Data.Linq.SqlClient.QueryConverter.VisitOrderBy(Expression sequence, LambdaExpression expression, SqlOrderType orderType) +109
   System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc) +6514
   System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc) +71
   System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +1114
   System.Data.Linq.SqlClient.QueryConverter.VisitFirst(Expression sequence, LambdaExpression lambda, Boolean isFirst) +32
   System.Data.Linq.SqlClient.QueryConverter.VisitSequenceOperatorCall(MethodCallExpression mc) +4898
   System.Data.Linq.SqlClient.QueryConverter.VisitMethodCall(MethodCallExpression mc) +71
   System.Data.Linq.SqlClient.QueryConverter.VisitInner(Expression node) +1114
   System.Data.Linq.SqlClient.QueryConverter.ConvertOuter(Expression node) +105
   System.Data.Linq.SqlClient.SqlProvider.BuildQuery(Expression query, SqlNodeAnnotations annotations) +119
   System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) +138
   System.Data.Linq.DataQuery`1.System.Linq.IQueryProvider.Execute(Expression expression) +58
   System.Linq.Queryable.FirstOrDefault(IQueryable`1 source) +220
   NewPower.Web.student_story.dis.Page_Load(Object sender, EventArgs e) in C:\Users\snow_\Desktop\np\NewPower.Web\NewPower.Web\student_story\dis.aspx.cs:23
   System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +52
   System.Web.UI.Control.OnLoad(EventArgs e) +97
   System.Web.UI.Control.LoadRecursive() +61
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +693


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4330.0