VS 2005 Debugger Features

Visual Studio 2005 Beta 1 is released at last! Previously known as Whidbey (and internally it will forever known as Whidbey, as 7.1 is forever Everett, as 7.0 is, er, 7.0) this beta is going to be available to MSDN Universal subscribers, and some other ways too (see later).

VS 2005 Debugger Features

New DataTips. Remember back to Visual C++ 4.0 (I think) that first brought you DataTips? Well think of those same tips, but on crack, and you get New Datatips. You can inspect whole objects in the datatips now, kind of a floating Watch window. It is the most important improvement to the debugger since, well, since VC2 really.
Tracepoints. A tracepoint is a breakpoint that doesn’t stop. Well instead of stopping, they print messages. Anything you like, including text, variables, stack traces, anything you like really. They are a great way to add logging to code without having to rebuild a thing.

Source file checksums. Ever got the debugger confused by having two different source files with the same name but in different paths? We have, and lots of other people too (especially default.aspx). The confusion is over: the C++, C# and VB compilers now emit a checksum of the source file into the debug info, so the debugger can tell if it got the right version or not. This makes breakpoints bind to the right source file even in the case of multiple matching basenames, something that has troubled us (and users) forever. (Note that checksums are not generated for ASP.NET compiles in beta 1).

Visualizers. Using a complex managed type that is ugly to view in the Watch window (e.g. DataSet)? Now you can either use a built-in Visualizer, or write your own. For DataSet you see the data in a proper grid control, for example. You can view long strings in a text editor, or an XML viewer if you like. If you want to write your own Visualizer for your type, or a Frameworks type, go right ahead. It just takes a bit of C#.
STL Data Display. STL types have always been a challenge for the debugger. In VC6 the debug format truncated the managled names at 255 bytes so you often couldn’t even manually look at the structure of some STL objects. This is fixed in 7.0, but ugly data structures are still ugly even if you can see more of them. VS Whidbey has a meta-language that lets you define exactly how to display complex types and includes support for all the common STL types. A hash table displays as an array in the debugger now, instead of that ugly thing it really is.
64-bit Support. Both native and managed debuggers support AMD64 and IA64 debugging now, with good feature parity with 32-bit, though no Edit & Continue or Mixed debugging.

Storing and Reading Base64 Encoded Connection String in Web.Config
Introduction
Many people store database connection string in web.config file. However, web.config file being an XML file, the data stored there is in clear text format. This is especially important for connection strings because anybody can easily see your database details including user id and password. In this article we will see how you can encrypt values stored in web.config using Base64 encoding and later on decrypt them in your code. Note that Base64 encoding is not a secure algorithm but it is a quick and easy way to hide the connection string details from casual readers.
Storing custom values in web.config
You store custom configuration values in web.config using section. The section looks like this:
<appSettings>
<add key="connectionstring"
value="data source=.\vsdotnet;initial
catalog=Northwind;user id=sa;password=mypassword"/>
</appSettings>
In short you store key-value pairs inside the section.
Encrypting connection string
In order to encrypt above connection string we will be using System.Convert class. We will build a small console application that allows us to pass plain connection string as command line argument and then displays encrypted version on the console.
The code looks like this:

Public Shared Sub Main(args() As String)
Dim data() As Byte = System.Text.ASCIIEncoding.ASCII.GetBytes(args(0))
Dim str As String = Convert.ToBase64String(data)
Console.WriteLine(str)
End Sub
Here, we are using System.Text.ASCIIEncoding.ASCII class to convert the connection string to an array of bytes. This is necessary because the Convert class function ToBase64String() expects array of bytes and then returns Base64 encoded version of it.
You can invoke above application (I created it as Base64Encrypter.exe) at command prompt like this:

Base64Encrypter.exe "data source=.\vsdotnet;initial catalog=Northwind;user id=sa;password=mypassword"
The output will be:
ZGF0YSBzb3VyY2U9Llx2c2RvdG5ldDtpbml0aWFsIGNhdGFsb2c9Tm9ydGh3aW5kO3VzZXIgaWQ9c2E7
cGFzc3dvcmQ9bXlwYXNzd29yZA==

You can now copy-paste this encoded version of the connection string in the web.config. The new appSettings section will look like this:
<appSettings>
<add key="connectionstring" value="ZGF0YSBzb3VyY2U9Llx2c2RvdG5ldDtpbml0aWFsIGNhdGFsb2c9Tm9ydGh3aW5kO3VzZXIgaWQ9c2E7
cGFzc3dvcmQ9bXlwYXNzd29yZA=="/>
</appSettings>

Reading the encrypted connection string back

Now, let us see how we can read the encrypted connection string and decrypt it so that we can use it further.


Dim data() As Byte = Convert.FromBase64String
(ConfigurationSettings.AppSettings("connectionstring"))
str = System.Text.ASCIIEncoding.ASCII.GetString(data)


Here, we again used the Convert class and called its FromBase64String function. This function accepts Base64 encoded string and returns a byte array. In order to retrieve the appSetting value we used ConfigurationSettings class as shown above. Finally, we used ASCII class again to convert the byte array to a string.

Facts behind Response.Redirect method

Whenever Response.Redirect line is executed, the browser gets a HTTP status code of 302 from the server indicating it to GET/POST again to the new URL provided. This means that the page does one more round trip to the server with different URL. Most of the browser use GET request to comply with HTTP standards and if they use POST then they would have to prompt the user for permission. In anycase there is a performance hit of posting twice. Most of the cases it is not visible to the user.

If you are very high on performance then use Server.Transfer instead. Also note that your form variables are not available in the next page in case of Response.Redirect; in case of Server.Transfer the data submitted by the user is preserved.

Advanced C# interview questions .NET

Advanced C# interview questions .NET
1. What’s the advantage of using System.Text.StringBuilder over System.String? StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it’s being operated on, a new instance is created.
2. Can you store multiple data types in System.Array? No.
3. What’s the difference between the System.Array.CopyTo() and System.Array.Clone()? The first one performs a deep copy of the array, the second one is shallow.
4. How can you sort the elements of the array in descending order? By calling Sort() and then Reverse() methods.
5. What’s the .NET datatype that allows the retrieval of data by a unique key? HashTable.
6. What’s class SortedList underneath? A sorted HashTable.
7. Will finally block get executed if the exception had not occurred? Yes.
8. What’s the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception? A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
9. Can multiple catch blocks be executed? No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
10. Why is it a bad idea to throw your own exceptions? Well, if at that point you know that an error has occurred, then why not write the proper code to handle that error instead of passing a new Exception object to the catch block? Throwing your own exceptions signifies some design flaws in the project.
11. What’s a delegate? A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
12. What’s a multicast delegate? It’s a delegate that points to and eventually fires off several methods.
13. How’s the DLL Hell problem solved in .NET? Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
14. What are the ways to deploy an assembly? An MSI installer, a CAB archive, and XCOPY command.
15. What’s a satellite assembly? When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
16. What namespaces are necessary to create a localized application? System.Globalization, System.Resources.
17. What’s the difference between // comments, /* */ comments and /// comments? Single-line, multi-line and XML documentation comments.
18. How do you generate documentation from the C# file commented properly with a command-line compiler? Compile it with a /doc switch.
19. What’s the difference between and XML documentation tag? Single line code example and multiple-line code example.
20. Is XML case-sensitive? Yes, so and are different elements.
21. What debugging tools come with the .NET SDK? CorDBG – command-line debugger, and DbgCLR – graphic debugger. Visual Studio .NET uses the DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.
22. What does the This window show in the debugger? It points to the object that’s pointed to by this reference. Object’s instance data is shown.
23. What does assert() do? In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.
24. What’s the difference between the Debug class and Trace class? Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug and release builds.
25. Why are there five tracing levels in System.Diagnostics.TraceSwitcher? The tracing dumps can be quite verbose and for some applications that are constantly running you run the risk of overloading the machine and the hard drive there. Five levels range from None to Verbose, allowing to fine-tune the tracing activities.
26. Where is the output of TextWriterTraceListener redirected? To the Console or a text file depending on the parameter passed to the constructor.
27. How do you debug an ASP.NET Web application? Attach the aspnet_wp.exe process to the DbgClr debugger.
28. What are three test cases you should go through in unit testing? Positive test cases (correct data, correct output), negative test cases (broken or missing data, proper handling), exception test cases (exceptions are thrown and caught properly).
29. Can you change the value of a variable while debugging a C# application? Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
30. Explain the three services model (three-tier application). Presentation (UI), business (logic and underlying code) and data (from storage or other sources).
31. What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET? SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but it’s a .NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a deprecated layer provided for backward compatibility to ODBC engines.
32. What’s the role of the DataReader class in ADO.NET connections? It returns a read-only dataset from the data source when the command is executed.
33. What is the wildcard character in SQL? Let’s say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve ‘La%’.
34. Explain ACID rule of thumb for transactions. Transaction must be Atomic (it is one unit of work and does not dependent on previous and following transactions), Consistent (data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t), Isolated (no transaction sees the intermediate results of the current transaction), Durable (the values persist if the data had been committed even if the system crashes right after).
35. What connections does Microsoft SQL Server support? Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords).
36. Which one is trusted and which one is untrusted? Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.
37. Why would you use untrusted verificaion? Web Services might use it, as well as non-Windows applications.
38. What does the parameter Initial Catalog define inside Connection String? The database name to connect to.
39. What’s the data provider name to connect to Access database? Microsoft.Access.
40. What does Dispose method do with the connection object? Deletes it from the memory.
41. What is a pre-requisite for connection pooling? Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings.


Accessing the database engine using SOAP via HTTP

Introduction

Microsoft® SQL Server™ 2005 provides a standard mechanism for accessing the database engine using SOAP via HTTP. Using this mechanism, you can send SOAP/HTTP requests to SQL Server to execute:
• Transact-SQL batch statements, with or without parameters.
• Stored procedures, extended stored procedures, and scalar-valued user-defined functions.
Prior to SQL Server 2005, the only mechanism available to connect to SQL Server was through a custom binary protocol named Tabular Data Stream (TDS). With SOAP/HTTP access, we have provided an open and documented protocol that may be used as an alternative to connect to SQL Server. Providing SOAP/HTTP access enables a broader range of clients to access SQL Server, including "zero foot print" clients, because there is no longer a need to have a Microsoft Data Access Components (MDAC) stack installed on the client device trying to connect to SQL Server. It facilitates interoperability with .NET, SOAP Toolkit, Perl, and more on a variety of platforms. Since the SOAP/HTTP access mechanism is based on well-known technologies such as XML and HTTP, it inherently promotes interoperability and access to SQL Server in a heterogeneous environment. Any device that can parse XML and submit HTTP requests can now access SQL Server.
Many enterprises have heterogeneous environments in which applications that run on UNIX and Linux platforms might require connectivity to SQL Server. Traditionally, the only solution available to such users was to use either JDBC or ODBC drivers. The SOAP/HTTP access now provides another, low-cost alternative. It is extremely useful for scenarios where DBA's have scripts written in Perl that run on UNIX and manage a SQL Server resource. It is also useful in developing client applications that connect to SQL Server using smart integrated development environments (IDEs) that have built-in SOAP/HTTP support, such as Microsoft Visual Studio® .NET or Jbuilder. These IDEs generate proxy code that abstracts the communication with SQL Server and provides objects that the client applications can use. Using SOAP/HTTP also enables anytime, anywhere access to SQL Server, which makes it easier to develop applications for mobile or sporadically connected devices. Once a connection has been established and the server has started processing requests, it can be monitored using existing mechanisms that TDS-based clients such as sqlclient, ODBC, and OLEDB use.

Requirements

SQL Server 2005–native Web services require Microsoft Windows Server™ 2003 as the operating system, because they rely on the kernel mode http driver http.sys that this version provides. Since SQL Server leverages the kernel mode http.sys driver, you do not necessarily need to have IIS installed to expose Web services out of SQL Server; this simplifies administration. Instead, you should base your decision to install IIS on application requirements. For example, certain applications benefit from having an explicit middle tier. In such cases, IIS would be useful.

HTTP Endpoints

Setting up SQL Server as a Web Service that can listen natively for HTTP SOAP requests requires creating an HTTP endpoint and defining the methods that the endpoint exposes. When an HTTP endpoint is created, it must be created

--->Extract from MSN Groupz..

C# Interview Questions

C# Question
1. What is the namespace used to access the information about the Assembly in C#?
2. What are indexes in C# (do not confuse with indexes in sqlserver).
3. What are indexes in C# (do not confuse with indexes in sqlserver).
4. what is protected in C#?
5. what is difference between read only and constant statement?
6. What is Internal? & protected internal?
7. How to raise an event and pass information from a user control
8. Usercontrols in Winforms
9. Private Constructor, what it is? Its use & Advantage?
10. What is Static Constructor? It’s use? Will it executed when we call the static method each time or only at 1st time?
11. What is Custom attribute? How to create? Namespace to access it? If I'm having custom attribute in an assembly, how to say that name in the code?
12. What is the usage of “internal” access specifier
13. What is Event Delegate, clear syntax for writing a event delegate
14. What is static constructor, when it will be fired? and what is its use
15. Can you create instance of a class which has Private Constructor
16. Question related to Access modifiers
17. OOPS Methodology in C#
18. Mechanism of a Garbage Collector
19. What are OOPS Concepts?
20. What is the Difference between a Structure and a Class?
21. What is an Interface? What are the available Interfaces in COM?
22. What are Sealed Classes in C#?
23. How to Override a function in C#?
24. Design related questions, C#, OOPS
25. What r the access specifiers in C#
26. Difference between Protected & Protected Internal
27. What specifier u used when u want to create once and use it
28. When to use Interface & Abstract ,give the exact scenario with example
29. Difference between static constructor / type constructor
30. I have 3 overloaded constructors in my class. In order to avoid making instance of the class do I need to make all constructors to private? Overloaded constructor will call default constructor internally?
31. In which Scenario you will go for Interface or Abstract Class?
32. Difference between static constructor / type constructor
33. What is Type Constructor and Instance Constructor (Static Constructor and Instance Constructor)
34. What are the Access Specifiers in C#
35. Have a look at the following class Public class Employee { private int Emplyeeage 25; private String employeename=”venkat” public static void displayempdetail() { MessageBox.Show(Employeeage+” “+EmployeeName) } public static void displayempdetail1() { Employee e1=new Employee(); e1.anotherFun(); } public void anotherFun() { MessageBox.Show(Employeeage+” “+EmployeeName) } } What would be the result if we call Employee.displayempdetail() ? Will It work
36. What the attributes in a Function Signature?
37. What access specifiers available in c#
38. Explain about Protected access and protected internal access
39. Difference between type constructor and instance constructor
40. In which cases you use Override and new base.
41. What data providers available in .net to connect to database and what are all things
42. What is Inheritance?
43. Difference between public and protected?
44. What is Overriding?
45. What is Overloading?
46. What is managed code & Unmanaged code?
47. C# language feature