NullReferenceException in Page_Load - asp.net

I have developed my project in asp.net 3.5. It works fine in localhost, when i published in the web sometimes its working fine but sometimes i am getting the following error. I think some error while conecting to the server but dont know exactly. Please help me to do it fine.
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.] Result.Page_Load(Object sender, EventArgs e) +128 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive() +50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

Enable debugging in your web.config file (Debug="True") and turn RemoteErrors="On". This will provide a much more detailed error message so that you can find what is throwing the NullReferenceException. Once solved, remember to reset these configurations.

Check the code inside your Page_Load method, its throwing a null refernce exception

HTTP Request pipeline is giving the issue here not the page.
you need to check and trace HTTPContext here

Related

Session Variables Work in Chrome, Firefox but Fail in IE11

We recently upgraded a web server to Win2012 (from 2008) and started using ActiveDirectory. The main web site uses an external order form written in C# (ASP.NET 2.0). Everything was working fine in the old server until we migrated. Now I get errors when trying to read Session variables in IE 11 (everything works with other browsers).
This is the error I get with the line causing it:
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:
Line 974: private void WriteTextConfirmation ()
Line 975: {
Line 976: string sFolders_OrderForm = Session ["Folders_OrderForm"].ToString ();
Line 977: string sOrderNumber = Session ["OrderNumber"].ToString ();
Line 978:
Source File: d:\Web Sites\Order Form\SubmitOrder.aspx.cs Line: 976
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
SubmitOrder.WriteTextConfirmation() in d:\Web Sites\Order Form\SubmitOrder.aspx.cs:976
SubmitOrder.Page_Load(Object sender, EventArgs e) in d:\Web Sites\Order Form\SubmitOrder.aspx.cs:1189
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +24
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +41
System.Web.UI.Control.OnLoad(EventArgs e) +131
System.Web.UI.Control.LoadRecursive() +65
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2427
The problem is that the Session variables that are being read are null. They should be set in the Default form and passed for use in the SubmitOrder form. These variables work with FireFox and Chrome but fail in IE. I'm not sure why this would occur.
We had the same problem and setting the session state to cookieless in Web.config fixed our problem.
Since you are saying that it is browser-specific, it would have to be a setting with the browser. Maybe you have cookies turned off?
Update
I did some searching, and it looks like it could still be cookie related.
Session variable empty in iis7 application
Another common cause of this issue is when the server name contains
underscores (e.g. DEV_TEST). Underscores aren't allowed as host names,
and could interfere with the ability to set cookies.
This Server Fault question has a few answers saying the same thing:
https://serverfault.com/questions/178733/iis-7-0-does-not-keep-session-variables
And another SO question saying underscores:: IE8 does not keep Session Variables
More from Google: https://www.google.com/search?q=iis+application+session+variables+IE

How to add custom sign in page for FBA application

I have configured FBA for my web application which is working fine with default sign in pages. So i wanted to create custonm sign in page for that application. For that i have created a custom sign in page. but when i entered credential it gives me an error as below.
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.]
LdapContosoAuthentication.Layouts.LdapContosoAuthentication.LoginCustmCntrlPage.Button1_Click(Object
sender, EventArgs e) +193
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +114
System.Web.UI.WebControls.Button.RaisePostBackEvent(String
eventArgument) +139
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler
sourceControl, String eventArgument) +28
System.Web.UI.Page.ProcessRequestMain(Boolean
includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
+2980
Can anyone tell me how can i solved that error?
Put your custom page in layout folder and make below changes. So you can open your custom login page:
<authentication mode="Forms">
<forms loginUrl="/_layouts/CustomLogin.aspx" />
</authentication>
Have you made any change in delegate control (login control) of login.aspx page?

IIS7 giving Object reference not set to an instance of an object error

I have an IIS7 application that is using the .net 4.0 framework. The application pool has the rights (read/write/execute) on the folder of the application and has (select/read/connect) rights to the Database. IIS7 accept the aspx files and everything seems fine int eh settings however i am getting a 404 error when I am calling ti from outside of the server.
When I go in the server and call the http://localhost link, i get this error
Server Error in '/Phonebook/PhoneBook' Application.
--------------------------------------------------------------------------------
Object reference not set to an instance of an object.
Description: An unhanded 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.]
PhoneBookApplication.DBUtils.Execute(SqlCommand command) +399
PhoneBookApplication._Default.FillddlSearch() +156
PhoneBookApplication._Default.Page_Load(Object sender, EventArgs e) +54
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +24
System.Web.UI.Control.LoadRecursive() +70
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3047
--------------------------------------------------------------------------------
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1
If I call a default-defaut.html file, it works, but not if I call the default-defaut.aspx. But in the daufault pages settings, both aspx and html are there.
Also, it seems to have something to do with the sql server, but I do not understand where to look to debug that
I have no idea what is doing this. Can someone help?
The method DBUtils.Execute seems to have an error. What do do you have on the page_load or any event before the page_load ?
The error is telling you exactly where the problem is:
Your line 399 of the DBUtils class has a bug:
PhoneBookApplication.DBUtils.Execute(SqlCommand command) +399
IIS is not the problem. If you are getting a 404 error is because you are not going to the correct URL.

asp v2.0 iis7 machine.config amended to contain maxconnection="192" stopped calls working to third party web services

I added the following to:
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\CONFIG\machine.config
<system.net>
<connectionManagement>
<add address="*" maxconnection="192" />
</connectionManagement>
</system.net>
After saving the application was running fine. However calls to third party web services/web method (MICROSOFT MAPPOINT, another API unrelated to Microsoft i.e two independent references) failed to work. One of which returned the following error:
--------------------------------------
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.]
WebApp.AddUpdate.LoadWebServiceRecord() +7740
WebApp.AddUpdate.MessageBox1_YesClicked(Object sender, EventArgs e) +51
WebApp.webcontrols.MessageBox.Yes_Click(Object sender, EventArgs e) +140
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +114
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +139
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +28
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2980
Version Information: Microsoft .NET Framework Version:2.0.50727.4206; ASP.NET Version:2.0.50727.4209
i.e exception above appears to have been created as it could no longer contact the service.
Remove the amendment in machine.config i.e remove the maxconnection rows and it all works fine again. Any idea why?
Do i need to declare the third party reference's in maxconnection?
if so would it be possible to provide and example?
Generally speaking, you shouldn't have to adjust it manually. ASP.NET 2 sets processModel to auto by default which among other things automatically scales maxconnections for the # of CPUs available (12N).
As to the error you're seeing, there must be more than meets than eye; the two are completely unrelated and there is no reason any maxconnection value would trigger a NullReferenceException in your application.
HTH
References:
http://technet.microsoft.com/en-us/magazine/2006.11.insidemscom.aspx
http://msdn.microsoft.com/en-us/library/7w2sway1.aspx

ASP.NET: "The resource class for this page was not found."

Myself and a colleague have recently upgraded to Windows Vista, and have been using it to develop ASP.NET applications with Visual Studio 2008 without many issues. And up until this morning, I had been managing to use local resources fine too.
However, this morning, my application suddenly stopped working with local resources, in the sense that any controls with a meta:resourcekey attribute suddenly display an empty string. At first, I thought it was something I had done to the application, so I created a brand new web application, added a label to an ASPX page, and generated a local resource from it. But running it has the same issue - the text simply isn't displayed. See attached screenshot for the example, and its output.
However, running it on my colleague's machine (who also has Vista), works without issue.
Incidently, if I try to get the value in the code behind, it throws this exception:
Server Error in '/Resources' Application. The resource class for this page was not found. Please check if the resource file exists and try again. 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: The resource class for this page was not found. Please check if the resource file exists and try again.
Source Error:
Line 12: protected void Page_Load(object sender, EventArgs e) Line 13: { Line 14: object x = HttpContext.GetLocalResourceObject("~/Default.aspx", "lblTestResource1.Text"); Line 15: } Line 16: }
Source File: C:\inetpub\wwwroot.Net2\Standalone\Resources\Resources\Default.aspx.cs Line: 14
Stack Trace:
[InvalidOperationException: The resource class for this page was not found. Please check if the resource file exists and try again.] System.Web.Compilation.LocalResXResourceProvider.CreateResourceManager()
+2468866 System.Web.Compilation.BaseResXResourceProvider.EnsureResourceManager()
+20 System.Web.Compilation.BaseResXResourceProvider.GetObject(String resourceKey, CultureInfo culture) +15 System.Web.Compilation.ResourceExpressionBuilder.GetResourceObject(IResourceProvider resourceProvider, String resourceKey, CultureInfo culture, Type objType, String propName) +21 System.Web.HttpContext.GetLocalResourceObject(String virtualPath, String resourceKey, CultureInfo culture) +38 System.Web.HttpContext.GetLocalResourceObject(String virtualPath, String resourceKey) +6 Resources._Default.Page_Load(Object sender, EventArgs e) in C:\inetpub\wwwroot.Net2\Standalone\Resources\Resources\Default.aspx.cs:14 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e)
+14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +99 System.Web.UI.Control.LoadRecursive()
+50 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627
Version Information: Microsoft .NET Framework Version:2.0.50727.3074; ASP.NET Version:2.0.50727.3074
Anyone have any idea? The weird thing is that using resources was working. I have tried restarting my computer, and clearing my Temporary ASP.NET files - but the issue remains.
Many thanks
Steve
Okay, I did a system restore to a couple of days previously, and it works fine now. Bizarre, as I (knowingly) made no changes to system files or anything.
As an extreme measure you could try a repair installation of the .net framework...
I've never encountered or even heard of this problem before so I'm afraid I don't have a better solution.

Resources