Server Error in '/' Application.

Value cannot be null.
Parameter name: String

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.ArgumentNullException: Value cannot be null.
Parameter name: String

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:


[ArgumentNullException: Value cannot be null.
Parameter name: String]
   System.Number.StringToNumber(String str, NumberStyles options, NumberBuffer& number, NumberFormatInfo info, Boolean parseDecimal) +13033611
   System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) +122
   lambda_method(Closure ) +95

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
   System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor) +0
   System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments) +91
   System.Delegate.DynamicInvokeImpl(Object[] args) +124
   System.Data.Linq.CommonDataServices.GetKeyFromPredicate(MetaType type, Dictionary`2 keys, Expression mex, Expression vex) +487
   System.Data.Linq.CommonDataServices.GetKeysFromPredicate(MetaType type, Dictionary`2 keys, Expression expr) +264
   System.Data.Linq.CommonDataServices.GetKeyValues(MetaType type, LambdaExpression predicate) +96
   System.Data.Linq.CommonDataServices.GetCachedObject(Expression query) +586
   System.Data.Linq.SqlClient.SqlProvider.GetCachedResult(Expression query) +44
   System.Data.Linq.SqlClient.SqlProvider.System.Data.Linq.Provider.IProvider.Execute(Expression query) +94
   System.Data.Linq.Table`1.System.Linq.IQueryProvider.Execute(Expression expression) +58
   System.Linq.Queryable.Single(IQueryable`1 source, Expression`1 predicate) +260
   Haghighi.Ext.UserControls.Pages.SingleNote.Page_Load(Object sender, EventArgs e) +1015
   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.Control.LoadRecursive() +134
   System.Web.UI.Control.LoadRecursive() +134
   System.Web.UI.Control.LoadRecursive() +134
   System.Web.UI.Control.LoadRecursive() +134
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +693


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4700.0