Dot Net preparation for interviews

The type was not expected. Use the XmlInclude or SoapInclude attribute to specify types that are not known statically

rishibhatnagar — Fri, 06 Aug 2010 15:12:03 +0000

This is an error that typically comes if you try to serialize a derived object and the serializer does not know of the derived class. There are some good explanations/solutions for this issue:

Event keyword

rishibhatnagar — Fri, 04 Jun 2010 04:25:22 +0000

Why do events use the event keyword and use a publisher-subscriber pattern instead of normally accessing the event method. Two points:

1. So, someone cannot accidentally set the delegate assignments to null. This would cause not only my own event to be “not invoked”, but also other people’s events will be not invoked.
2. Also, the event can (as it should) be invoked only from within the class.

http://msdn.microsoft.com/en-us/library/8627sbea(v=VS.100).aspx

Storing temporary data in a Stored procedure

rishibhatnagar — Thu, 15 Apr 2010 21:04:16 +0000

http://databases.aspfaq.com/database/should-i-use-a-temp-table-or-a-table-variable.html

Lock wait timeout exceeded; try restarting transaction

rishibhatnagar — Fri, 29 Jan 2010 19:57:47 +0000

I was getting this error, because in the MySQL Manager, I had a select query open, that probably had the table locked. Ughhh…

How to upload multiple files using AJAX

rishibhatnagar — Sun, 03 Jan 2010 19:57:40 +0000

http://localhost:58028/Common/VCardUpload.aspx

Integrating .Net with Active Directory (AD)

rishibhatnagar — Mon, 16 Nov 2009 19:55:45 +0000

http://www.c-sharpcorner.com/UploadFile/kb_sathya/DotNETActiveDirectory04172007013054AM/DotNETActiveDirectory.aspx

http://www.c-sharpcorner.com/UploadFile/john_charles/AccessingtheActiveDirectoryfromMicrosoftNET04172007154931PM/AccessingtheActiveDirectoryfromMicrosoftNET.aspx

http://www.c-sharpcorner.com/UploadFile/wojtekpiaseczny/AdamAuthentication10262006124310PM/AdamAuthentication.aspx

http://www.c-sharpcorner.com/UploadFile/ankithakur/Login_Using_Active_Directory04052006061801AM/Login_Using_Active_Directory.aspx

http://www.c-sharpcorner.com/UploadFile/rohit_kshirsagar/FormsAuthenticationActiveDirectory11262005074248AM/FormsAuthenticationActiveDirectory.aspx

ASP.Net control libraries

rishibhatnagar — Wed, 28 Oct 2009 14:28:41 +0000

http://www.devexpress.com/Products/Free/WebRegistration60/
http://www.asp.net/Community/Control-gallery/
http://www.obout.com/index.aspx
http://www.blocks4.net/FreeProducts/FreeProducts0.aspx

IIS and ASP.Net authentication

rishibhatnagar — Tue, 27 Oct 2009 14:55:04 +0000

ASP.NET runs inside the process of IIS due to which there are two authentication layers which exist in the system. First authentication happens at the IIS level and the second at ASP.NET level per the WEB.CONFIG file.

Working:

At first, IIS ensures that the incoming request is from an authenticated IP address. Otherwise the request is rejected. By default IIS allows anonymous access due to which requests are automatically authenticated. However, if this is changed, IIS performs its own user authentication too.
ASP.net checks if impersonation is enabled if a request is passed to ASP.net by an authenticated user. If it is enabled, ASP.net acts itself as an authenticated user else it acts with its own configured account.
Finally the OS resources are requested by the identity obtained from previous step.
The user is granted the resources if the authentication is successful else the resources are denied.

Resources can include ASP.net page, code access security features to extend authorization step to disk files, registry keys, etc

Authentication vs Authorization

rishibhatnagar — Tue, 27 Oct 2009 14:53:12 +0000

Authentication is the process of verifying user’s identity. Authorization is the process of granting privilege to authenticated user. The user is validated using authenticated process and then the authorization process identifies if the user has access to a given resource. In ASP.NET, you can authenticate user in code or allow the user to be authenticated by other party such as MS Passport. You have two layer of authentication in ASP.NET i.e. IIS layer and ASP.net authentication process layer. IIS performs authentication if it is configured to do so. By default, IIS allows anonymous access which means all the users are authenticated. All the requests pass through IIS layer and then to ASP.NET authentication process.
If any user requests IIS layer for anonymous access, the user is treated
as authenticated and pass to ASP.NET process. ASP.NET checks if impersonation
is enabled in the web configuaration file i.e. web.config file. If
impersonation is enabled, ASP.net acts as though it were the authenticated user
otherwise it process with its own configured account.

To enable the application to authenticate users,

you need to add element in the authorization
section of Web.config.

What is the authentication mode available in ASP.NET?

Answer - ASP.NET supports three
authentication modes through the System.Web.Security namespace.

Windows Authentication

The windows authentication authenticates users based on their windows accounts.
In short, it uses windows network security. It uses IIS to perform
authentication.

Passport authentication

The Passport authentication uses Microsoft’s passport service to authenticate
users. The new user is directed to the Microsoft site where he can register his
identity. This facilitates user to access multiple sites using single user name
and password. You need to install the Passport SDK to enable the Passport
classes in the System.Web.Security namespace.

Form authentication

The Form authentication collects user’s credential and lets the application use
own logic to authenticate users. The collected user’s credential is validated
using the list maintained by the application. The application maintains its own
user list either using
element in the
web.config file or using database. The advantage of using form
authentication is that the users don’t need to be the member
of windows network to have access to the application.

How to make a method of a web service class accessible through the internet?

rishibhatnagar — Tue, 27 Oct 2009 14:50:04 +0000

By qualifying the method with the WebMethod attribute.

[WebMethod()]
public string MethodName()

The WebMethod attribute provides the following properties: