C# interview
C# interview questions and answers
C# interview questions and answers
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.
Can you store multiple data types in System.Array?
No.
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.
By calling Sort() and then Reverse() methods.
What's the .NET datatype that allows the retrieval of data by a unique key?
HashTable.
What's class SortedList underneath?
A sorted HashTable.
Will finally block get executed if the exception had not occurred?
Yes.
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 {}.
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.
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.
A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
It's a delegate that points to and eventually fires off several methods.
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, System.Resources.
Single-line, multi-line and XML documentation comments.
Compile it with a /doc switch.
Single line code example and multiple-line code example.
Yes, so <Student> and <student> are different elements.
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.
It points to the object that's pointed to by this reference. Object's instance data is shown.
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 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.
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.
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).
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
Presentation (UI), business (logic and underlying code) and data (from storage or other sources).
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.
It returns a read-only dataset from the data source when the command is executed.
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%'.
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).
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords).
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.
Web Services might use it, as well as non-Windows applications.
The database name to connect to.
Provider=Microsoft.Jet.OLEDB.4.0;
Deletes it from the memory.
Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings.
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Hi buddy,
Nice collection of Interview questions.
Keep Posting.
Thanks