Server Error in '/' Application.

System.NullReferenceException: Object reference not set to an instance of an object.
at haidianjiaxiao.index.Load_Class_Index() in F:\xueche\haidianjiaxiao\index.aspx.cs:line 241
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: CSystem.CException: System.NullReferenceException: Object reference not set to an instance of an object.
at haidianjiaxiao.index.Load_Class_Index() in F:\xueche\haidianjiaxiao\index.aspx.cs:line 241
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:
[CException: System.NullReferenceException: Object reference not set to an instance of an object.
at haidianjiaxiao.index.Load_Class_Index() in F:\xueche\haidianjiaxiao\index.aspx.cs:line 241]
haidianjiaxiao.index.Load_Class_Index() in F:\xueche\haidianjiaxiao\index.aspx.cs:253
haidianjiaxiao.index.Page_Load(Object sender, EventArgs e) in F:\xueche\haidianjiaxiao\index.aspx.cs:37
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +47
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1436
Version Information: Microsoft .NET Framework Version:2.0.50727.1433; ASP.NET Version:2.0.50727.1433