Session is null when calling a web service in ASP.NET C#

Question

I have a Login Class which has a function: isCorrect() that takes username and password as two attributes And a asp.net WebService To allow using AJAX.

LoginService.cs

public Login CorrectLogin(string username, string password) 
{   
   Login thisLogin = Login.isCorrect(username, password);
   int thisLoggedinUserID = thisLogin.LoggedinUserID;

   if (thisLoggedinUserID != 0)
   {
      Session["loggedinUser"] = thisLoggedinUserID;
   }

   return thisLogin;
}

When I want to set value of Session["loggedinUser"] = thisLoggedinUserID this error accrues:

Object reference not set to an instance of an object.

I can't understand what is solution.

since its error happens on webservice class only stacktrace I found is : at LoginService.CurrectLogin(String username, String password) in f:\...\App_Code\LoginService.cs:line 19 — mhesabi
– mhesabi, Commented Mar 22, 2012 at 21:01

Dominic Zukiewicz · Accepted Answer · 2012-03-22 20:45:34Z

37

Web services don't have Session by default. Add an attribute to the WebMethod..

 [WebMethod(EnableSession=true)]
 public Login CurrentLogin .....

answered Mar 22, 2012 at 20:45

Dominic Zukiewicz

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McGarnagle · Accepted Answer · 2012-03-22 20:39:14Z

1

Looks like the Session object is null. Are you sure sessions are switched on in your application?

answered Mar 22, 2012 at 20:39

McGarnagle

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1 Comment

mhesabi Over a year ago

how can I know if its on? for example this is my web.config <sessionState timeout="60" mode="StateServer" stateNetworkTimeout="20"></sessionState>

Michael Hahn · Accepted Answer · 2012-03-22 20:42:43Z

0

Here is a good tutorial on login and access

http://www.mikesdotnetting.com/Article/75/Simple-Login-and-Redirect-for-ASP.NET-and-Access

Its not hard to find, i guess your making your own provider. codeplex etc has a bunch too.

answered Mar 22, 2012 at 20:42

Michael Hahn

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Comments

Neonamu · Accepted Answer · 2012-03-22 20:54:48Z

0

Sessions doesn't work well in Web Services c#. Few months ago I would do the same as you, but I change the system. Now I'm using a token identification (using a persistence layer): First you must login, and every time you'll make a call, you must send the token, in one parameter or a soap header or something like this. I Recommend to use SSL always.

Another option is to ident every web service call with login and password in a SOAPHeader, and use a SOAPExtension to autenticate or not the user-call. This method is only valid for SOAP protocol communication, not for HTTP POST or HTTP GET.

Hope this helps.

answered Mar 22, 2012 at 20:54

Neonamu

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