DOT NET – What is a cookie

Recently I got a message from one of the reader of my site that what exactly is a cookie. So I decided to wire a post dedicated to it .

  1. A cookie is name=value pair like variable which is stored as a file(persistant cookie) and which travels automatically between every request and response.
  2. Cookies are based on domains(website). As long as user is working with current web site cookie will be available.
  3. Cookies are maintained by browser but not by server which means cookies based websites are dependent on client.
  4. Cookies can be created as
    (i) In-memory cookie
    (ii) Persistant Cookie

An In-memory cookie means as long as user is working with app it will be available – also called as Session Cookie.

Persistant cookie means it will be stored in client physical location and available online as well as offline.

Reference : Dilip Kumar Jena ( )


Criticism associated with DOT NET


C# programs, like all programs written for the .NET and other virtual machine environments such as Java, tend to require more system resources than functionally similar applications that access machine resources more directly.


Microsoft’s current .NET implementation is only available on Windows.

Reference : Dilip Kumar Jena ( )

C Sharp (programming language) and History

C# is an object-oriented programming language developed by Microsoft as part of the .NET initiative and later approved as a standard by ECMA and ISO . Anders Hejlsberg leads development of the C# language, which has a procedural, object-oriented syntax based on C++ and includes influences from aspects of several other programming languages (most notably Delphi and Java) with a particular emphasis on simplification.


During the development of .NET, the class libraries were originally written in a language called Simple Managed C (SMC). In January 1999, Anders Hejlsberg formed a team to build a new language at the time called Cool. By the time the .NET project was publicly announced at the July 2000 Professional Developers Conference (PDC), the language had been renamed C# and the class libraries and ASP.NET runtime had been ported to C#.

C#’s principal designer and lead architect at Microsoft is Anders Hejlsberg, who was previously involved with the design of Visual J++, Borland Delphi, and Turbo Pascal. In interviews and technical papers he has stated that flaws in most major programming languages (e.g. C++, Java, Delphi, and Smalltalk) drove the fundamentals of the Common Language Runtime (CLR), which, in turn, drove the design of the C# programming language itself.

Reference : Dilip Kumar Jena ( )

Dot Net – How to upload excel sheet into databse using Dataset in ASP.NET

I thought of writing this blog post because there can a number of occasion where in you might need to upload something from word file or excel sheet or it can be any kind of  file need to be inserted into the database what we can do many things.

But probably what I feel good and follow most of the time is doing this way so that we can preserve the statements for future reference what we have actually used and where it is going to exactly affect.

Step 1: Create  a website and then add default page on to it.

Step 2: Write the following code in Page_Load(object sender, EventArgs e) function

DataSet ds = new DataSet();

OleDbConnection myCon = new OleDbConnection(@”Provider=Microsoft.Jet.OLEDB.4.0;Data Source=folderpath\sheet.xls;Extended Properties=Excel 8.0;”);

OleDbCommand myComm = new OleDbCommand(“select * from [sheet1$] where State<>””, myCon);

OleDbDataAdapter da = new OleDbDataAdapter(myComm);


for (int i = 0; i < ds.Tables[0].Rows.Count;i++ )


Response.Write(“insert into dbo.Temp2 values(‘” + ds.Tables[0].Rows[i][0].ToString() + “‘,'” + ds.Tables[0].Rows[i][1].ToString() + “‘,'” + ds.Tables[0].Rows[i][2].ToString() + “‘,'” + ds.Tables[0].Rows[i][3].ToString() + “‘)<br />”);



Step 3: Create a table in SQL Server names Temp2 where in u want insert the excel sheet into.

NOTE: The table name can be any name  you like its just an example never take it as standard, its for learing.

create table Temp2(Id varchar(10),country varchar(100),natAnimal varchar(50),lang varchar(50))

Step 4: Create or if u have  excel sheet just make sure that that contains header for each column it will be easy to understand


State Country Animal Language
1 Australia Kangroo English
2 India Peacock Hindi
3 USA American Biston English

This is a sample excel sheet name it as sheet and inside as Sheet1 it will be applied by default so just hit the save button.

So all set!!!

now save the excel sheet in the folder of your website and run the web site the expected Output will be something like this will appear in your broswer

insert into dbo.Temp2 values(‘1′,’Australia’,’Kangroo’,’English’)

insert into dbo.Temp2 values(‘2′,’India’,’Peacock ‘,’Hindi’)

insert into dbo.Temp2 values(‘3′,’USA’,’American Biston’,’English’)

then copy it and paste in ssms (SQL server Query Editor and hit F5 to execute) Finally records are inserted into the database.

There can be many more ways I am sure but this is also handy when you have production and development section seperate.

Reference : Dilip Kumar Jena ( )

DotNet FrameWork – What actually happens when you add something to an arraylistcollection – How Boxing and unboxing occures in memory – Why only boxed types can be unboxed – Day 30 of 30

What actually happens when you add  something to an arraylistcollection ?

Following things will happen :

Arraylist is a dynamic array class in c# in System.Collections namespace derived from interfaces – ICollection , IList , ICloneable , IConvertible  . It terms of in memory structure following is the implementation .

a. Check up the total space if there’s any free space on the declared list .

b. If yes add the new item and increase count by 1 .

c. If No Copy the whole thing to a temporary Array of Last Max. Size .

d. Create new Array with size ( Last Array Size + Increase Value )

e. Copy back values from temp and reference this new array as original array .

f. Must doing Method updates too , need to check it up .

What is Boxing and unboxing? Does it occure automaatically or u need to write code to box and unbox?

Boxing – Process of converting a System.ValueType to Reference Type , Mostly base class System.Object type and allocating it memory on Heap .Reverse is unboxing , but can only be done with prior boxed variables.

Boxing is always implicit but Unboxing needs to be explicitly done via casting , thus ensuring the value type contained inside .

How Boxing and unboxing occures in memory?

Boxing converts value type to reference type , thus allocating memory on Heap . Unboxing converts already boxed reference types to value types through explicit casting , thus  allocating memory on stack .

Why only boxed types can be unboxed?

Unboxing is the process of converting a Reference type variable to Value type and thus allocating memory on the stack . It happens only to those Reference type variables that have been earlier created by Boxing of a Value Type , therefore internally they contain a value type , which can be obtained through explicit casting . For any other Reference type , they don’t internally contain a Value type to Unboxed via explicit casting . This is why only boxed types can be unboxed .

Please read all the post in the Dotnet Framework series.

Reference : Dilip Kumar Jena ( )

DotNet FrameWork – difference between Finalize() and Dispose() – How is the using() pattern useful – What is Program Database (PDB) – Day 27 of 30

What is the difference between Finalize() and Dispose()?

Dispose() is called by the user of an object to indicate that he is finished with it, enabling that object to release any unmanaged resources it holds. Finalize() is called by the run-time to allow an object which has not had Dispose() called on it to do the same. However, Dispose() operates determinalistically, whereas there is no guarantee that Finalize() will be called immediately when an object goes out of scope – or indeed at all, if the program ends before that object is GCed – and as such Dispose() is generally preferred.

How is the using() pattern useful? What is IDisposable? How does it support deterministic finalization?

The using() pattern is useful because it ensures that Dispose() will always be called when a disposable object (defined as one that implements IDisposable, and thus the Dispose() method) goes out of scope, even if it does so by an exception being thrown, and thus that resources are always released.

What does this useful command line do? tasklist /m “mscor*”

Lists all the applications and associated tasks/process currently  running on the system with a module whose name begins “mscor” loaded into them; which in nearly all cases means “all the .NET processes”.

What’s wrong with a line like this? DateTime.Parse(myString);

There’s nothing wrong with this declaration.Converts the specified string representation of a date and time to its DateTime equivalent.But If the string is not a valid DateTime,It throws an exception.

What are PDBs? Where must they be located for debugging to work?

A program database (PDB) files holds debugging and project state information that allows incremental linking of debug configuration of your program.There are several different types of symbolic debugging information. The default type for Microsoft compiler is the so-called PDB file. The compiler setting for creating this file is /Zi, or /ZI for C/C++(which creates a PDB file with additional information that enables a feature called “”Edit and Continue””) or a Visual Basic/C#/JScript .NET program with /debug.

A PDB file is a separate file, placed by default in the Debug project subdirectory, that has the same name as the executable file with the extension .pdb. Note that the Visual C++ compiler by default creates an additional PDB file called VC60.pdb for VisulaC++6.0 and VC70.PDB file for VisulaC++7.0. The compiler creates this file during compilation of the source code, when the compiler isn’t aware of the final name of the executable. The linker can merge this temporary PDB file into the main one if you tell it to, but it won’t do it by default. The PDB file can be useful to display the detailed stack trace with source files and line numbers.

What is FullTrust? Do GAC’ed assemblies have FullTrust?

Before the .NET Framework existed, Windows had two levels of trust for downloaded code. This old model was a binary trust model. You only had two choices: Full Trust, and No Trust. The code could either do anything you could do, or it wouldn’t run at all.

The permission sets in .NET include FullTrust, SkipVerification, Execution, Nothing, LocalIntranet, Internet and Everything. Full Trust Grants unrestricted permissions to system resources. Fully trusted code run by a normal, nonprivileged user cannot do administrative tasks, but can access any resources the user can access, and do anything the user can do. From a security standpoint, you can think of fully trusted code as being similar to native, unmanaged code, like a traditional ActiveX control.

GAC assemblies are granted FullTrust. In v1.0 and 1.1, the fact that assemblies in the GAC seem to always get a FullTrust grant is actually a side effect of the fact that the GAC lives on the local machine.  If anyone were to lock down the security policy by changing the grant set of the local machine to something less than FullTrust, and if your assembly did not get extra permission from some other code group, it would no longer have FullTrust even though it lives in the GAC.

What does this do? gacutil /l | find /i “Corillian”

The Global Assembly Cache tool allows you to view and manipulate the contents of the global assembly cache and download cache.The tool comes with various optional params to do that.

“”/l”” option Lists the contents of the global assembly cache. If you specify the assemblyName parameter(/l [assemblyName]), the tool lists only the assemblies matching that name.

What does this do .. sn -t foo.dll ?

Sn -t option displays the token for the public key stored in infile. The contents of infile must be previously generated using -p.

Sn.exe computes the token using a hash function from the public key. To save space, the common language runtime stores public key tokens in the manifest as part of a reference to another assembly when it records a dependency to an assembly that has a strong name. The -tp option displays the public key in addition to the token.

How do you generate a strong name?

.NET provides an utility called strong name tool. You can run this toolfrom the VS.NET command prompt to generate a strong name with an option “-k” and providing the strong key file name. i.e. sn- -k < file-name >

What is the difference between a Debug and Release build? Is there a significant speed difference? Why or why not?

The Debug build is the program compiled with full symbolic debug information and no optimization. The Release build is the program compiled employing  optimization and contains no symbolic debug information. These settings can be changed as per need from Project Configuration properties. The release runs faster since it does not have any debug symbols and is optimized.

Explain the use of virtual, sealed, override, and abstract.

Abstract: The keyword can be applied for a class or method.

1. Class: If we use abstract keyword for a class it makes the

class an abstract class, which means it cant be instantiated. Though

it is not nessacary to make all the method within the  abstract class to be virtual. ie, Abstract class can have concrete methods

2. Method: If we make a method as abstract, we dont need to provide implementation

of the method in the class but the derived class need to implement/override this method.

Sealed: It can be applied on a class and methods. It stops the type from further derivation i.e no one can derive class

from a sealed class,ie A sealed class cannot be inherited.A sealed class cannot be a abstract class.A compile time error is thrown if you try to specify sealed class as a  base class.

When an instance method declaration includes a sealed modifier, that method is said to be a sealed method. If an instance method declaration includes the sealed modifier, it must also include the override modifier. Use of the sealed modifier prevents a derived class from further overriding the method  For Egs: sealed override public void Sample() { Console.WriteLine(“Sealed Method”); }

Virtual & Override: Virtual & Override keywords provides runtime polymorphism. A base class can make some of its methods

as virtual which allows the derived class a chance to override the base class implementation by using override keyword.

For e.g. class Shape


int a

public virtual void Display()





class Rectangle:Shape


public override void Display()





Explain the importance and use of each, Version, Culture and PublicKeyToken for an assembly.

This three along with name of the assembly provide a strong name or fully qualified name to the assembly. When a assembly is referenced with all three.

PublicKeyToken: Each assembly can have a public key embedded in its manifest that identifies the developer. This ensures that once the assembly ships, no one can modify the code or other resources contained in the assembly.

Culture: Specifies which culture the assembly supports

Version: The version number of the assembly.It is of the following form

Explain the differences between public, protected, private and internal.

These all are access modifier and they governs the access level. They can be applied to class, methods, fields.

Public: Allows class, methods, fields to be accessible from anywhere i.e. within and outside an assembly.

Private: When applied to field and method allows to be accessible within a class.

Protected: Similar to private but can be accessed by members of derived class also.

Internal: They are public within the assembly i.e. they can be accessed by anyone within an assembly but outside assembly they are not visible.

Please read all the post in the Dotnet Framework series.

Reference : Dilip Kumar Jena ( )