interview

Does C# support multiple-inheritance?

Who is a protected class-level variable available to?

Are private class-level variables inherited?

Describe the accessibility modifier “protected internal”.

What’s the top .NET class that everything is derived from?

What does the term immutable mean?

What’s the difference between System.String and System.Text.StringBuilder classes?

What’s the advantage of using System.Text.StringBuilder over System.String?

No.

The Clone() method returns a new array (a shallow copy) object containing all the elements in the original array. The CopyTo() method copies the elements into another existing array. Both perform a shallow copy. A shallow copy means the contents (each array element) contains references to the same object as the elements in the original array. A deep copy (which neither of these methods performs) would create a new instance of each element's object, resulting in a different, yet identacle object.

11 . How can you sort the elements of the array in descending order?

By calling Sort() and then Reverse() methods.

HashTable.

Yes.

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 {}.

No. Once the proper catch block processed, control is transferred to the finally block (if there are any).

Presentation (UI), Business (logic and underlying code) and Data (from storage or other sources).

Class Questions

Place a colon and then the name of the base class.

Yes. The keyword “sealed” will prevent the class from being inherited.

Yes. Just leave the class public and make the method sealed.

A class that cannot be instantiated. An abstract class is a class that must be inherited and have the methods overridden. An abstract class is essentially a blueprint for a class without any implementation.

1. When the class itself is inherited from an abstract class, but not all base abstract methods have been overridden.

Interfaces, like classes, define a set of properties, methods, and events. But unlike classes, interfaces do not provide implementation. They are implemented by classes, and defined as separate entities from classes.

They all must be public, and are therefore public by default.

Yes. .NET does support multiple interfaces.

It’s up to you to implement the method inside your own class, so implementation is left entirely up to you. This might cause a problem on a higher-level scale if similarly named methods from different interfaces expect different data, but as far as compiler cares you’re okay.

In an interface class, all methods are abstract - there is no implementation. In an abstract class some methods can be concrete. In an interface class, no accessibility modifiers are allowed. An abstract class may have accessibility modifiers.

Structs are value-type variables and are thus saved on the stack, additional overhead but faster retrieval. Another difference is that structs cannot inherit.

Method and Property Questions

Value. The data type of the value parameter is defined by whatever data type the property is declared as.

The method or property can be overridden.

When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.

31 . Can you declare an override method to be static if the original method is not static?

No. The signature of the virtual method must remain the same. (Note: Only the keyword virtual is changed to keyword override)

Different parameter data types, different number of parameters, different order of parameters.

Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.

Events and Delegates

A delegate object encapsulates a reference to a method.

A delegate that has multiple handlers assigned to it. Each assigned handler (method) is called.

Yes.

Single-line comments, multi-line comments, and XML documentation comments.

Compile it with the /doc switch.

Debugging and Testing Questions

1. CorDBG – command-line debugger. To use CorDbg, you must compile the original C# file using the /debug switch.

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.

Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug and release builds.

The tracing dumps can be quite verbose. For applications that are constantly running you run the risk of overloading the machine and the hard drive

To the Console or a text file depending on the parameter passed to the constructor.

Attach the aspnet_wp.exe process to the DbgClr debugger.

Yes. If you are debugging via Visual Studio.NET, just go to Immediate window.

ADO.NET and Database

It returns a read-only, forward-only rowset from the data source. A DataReader provides fast access when a forward-only sequential read is needed.

SQL ServerNET 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. OLE-DB.NET is a .NET layer on top of the OLE layer, so it’s not as fastest and efficient as SqlServer.NET.

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%’.

A transaction must be:

51 . What connections does Microsoft SQL Server support?

Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and password).

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.

The database name to connect to.

Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings. The connection string must be identical.

Assembly Questions

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.

An MSI installer, a CAB archive, and XCOPY command.

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.

System.Globalization and System.Resources.

An Assembly.

As a good rule, you should not call the garbage collector. However, you could call the garbage collector when you are done using a large object (or set of objects) to force the garbage collector to dispose of those very large objects from memory. However, this is usually not a good practice.

Use Boxing.

Boxing converts a value-type to a reference-type, thus storing the object on the heap. Unboxing converts a reference-type to a value-type, thus storing the value on the stack.

31 . Which control would you use if you needed to make sure the values in two different controls matched?

Web Service Questions

State Management Questions

Sometimes it is necessary to carry a particular session data across pages.

MSIL is Microsoft Intermediate (Intermediary) Language. It is Microsoft's implementation of CIL (standard recognized

.NET supports more than 21 language (I think 24 now). They compile to IL first and then this IL would get JITted to Native

Out of all the Page_Load is the one where your code gets loaded and your magic should be written. page_init

63 . What property do you have to set to tell the grid which page to go to when using the Pager object?

Array

? easy to find the nth element in the array by directly referencing them by their position in the array.[ arrays allow random access ] , O(1)