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.NET dotnet windows services interview questions
1) What is
.NET Framework?
Is .NET a runtime service or a development platform? Answer
It’s bothand actually a lot more. Microsoft .NET is a
company-wide initiative. It includes a new way of delivering
software and services to businesses and consumers. A part of
Microsoft.NET is the .NET Frameworks. The frameworks is the
first part of the MS.NET initiate to ship and it was given
out to attendees at the PDC in July. The .NET frameworks
consists of two parts: the .NET common language runtime and
the .NET class library. These two components are packaged
together into the .NET Frameworks SDK which will be
available for free download from Microsoft’s MSDN web site
later this month. In addition, the SDK also includes
command-line compilers for C#, C++, JScript, and VB. You use
these compilers to build applications and components. These
components require the runtime to execute so this is a
development platform. When Visual Studio.NET ships, it will
include the .NET SDK and a GUI editor, wizards, tools, and a
slew of other things. However, Visual Studio.NET is NOT
required to build .NET applications.
New features of Framework 1.1 ?
What is CLR? How it will work?
What is MSIL, IL, CTS?
What is JIT and how is works
What is strong name? A name that consists of an assembly’s
identity—its simple text name, version number, and culture
information (if provided)—strengthened by a public key and a
digital signature generated over the assembly.
What is portable executable (PE) The file format defining
the structure that all executable files (EXE) and Dynamic
Link Libraries (DLL) must use to allow them to be loaded and
executed by Windows. PE is derived from the Microsoft Common
Object File Format (COFF). The EXE and DLL files created
using the .NET Framework obey the PE/COFF formats and also
add additional header and data sections to the files that
are only used by the CLR. The specification for the PE/COFF
file formats is available at http://www.microsoft.com/whdc/hwdev/hardware/pecoffdown.mspx
Which is the base class for .net Class library? Ans:
system.object
What is Event? Delegate, clear syntax for writing a event
delegate// keyword_delegate.cs // delegate declaration
delegate void MyDelegate(int i);
class Program
{
public static void Main()
{
TakesADelegate(new MyDelegate(DelegateFunction));
}
public static void TakesADelegate(MyDelegate SomeFunction)
{
SomeFunction(21);
}
public static void DelegateFunction(int i)
{
System.Console.WriteLine(\"Called by delegate withnumber:
{0}.\", i);
}
}ment DataGrid in .NET? How would you make a combo-box
appear in one column of a DataGrid? What are the ways to
show data grid inside a data grid for a master details type
of tables?
If we write any code for DataGrid methods, what is the
access specifier used for that methods in the code behind
file and why?
What is Application Domain? Application domains provide a
unit of isolation for the common language runtime. They are
created and run inside a process. Application domains are
usually created by a runtime host, which is an application
responsible for loading the runtime into a process and
executing user code within an application domain. The
runtime host creates a process and a default application
domain, and runs managed code inside it. Runtime hosts
include ASP.NET, Microsoft Internet Explorer, and the
Windows shell.
What is serialization in .NET? What are the ways to control
serialization? Serialization can be defined as the process
of storing the state of an object to a storage medium.
During this process, the public and private fields of the
object and the name of the class, including the assembly
containing the class, are converted to a stream of bytes,
which is then written to a data stream. When the object is
subsequently deserialized, an exact clone of the original
object is created.
Binary serialization preserves type fidelity, which is
useful for preserving the state of an object between
different invocations of an application. For example, you
can share an object between different applications by
serializing it to the clipboard. You can serialize an object
to a stream, disk, memory, over the network, and so forth.
Remoting uses serialization to pass objects “by value” from
one computer or application domain to another.
XML serialization serializes only public properties and
fields and does not preserve type fidelity. This is useful
when you want to provide or consume data without restricting
the application that uses the data. Because XML is an open
standard, it is an attractive choice for sharing data across
the Web. SOAP is an open standard, which makes it an
attractive choice.
What are the different authentication modes in the .NET
environment?
<authentication mode=”Windows|Forms|Passport|None”>
<forms name=”name” loginUrl=”url”
protection=”All|None|Encryption|Validation”
timeout=”30″ path=”/” > requireSSL=“true|false”
slidingExpiration=“true|false”><
credentials passwordFormat=”Clear|SHA1|MD5″><
user name=”username” password=”password”/>
</credentials> </forms>
<passport redirectUrl=\"internal\"/>
</authentication>/li>
What is the use of trace utility
What is different between User Control and Web Control and
Custom Control?
What is exception handling? When an exception occurs, the
system searches for the nearest catch clause that can handle
the exception, as determined by the run-time type of the
exception. First, the current method is searched for a
lexically enclosing try statement, and the associated catch
clauses of the try statement are considered in order. If
that fails, the method that called the current method is
searched for a lexically enclosing try statement that
encloses the point of the call to the current method. This
search continues until a catch clause is found that can
handle the current exception, by naming an exception class
that is of the same class, or a base class, of the run-time
type of the exception being thrown. A catch clause that
doesn’t name an exception class can handle any exception.
Once a matching catch clause is found, the system prepares
to transfer control to the first statement of the catch
clause. Before execution of the catch clause begins, the
system first executes, in order, any finally clauses that
were associated withtry statements more nested that than the
one that caught the exception. Exceptions that occur during
destructor execution are worthspecial mention. If an
exception occurs during destructor execution, and that
exception is not caught, then the execution of that
destructor is terminated and the destructor of the base
class (if any) is called. If there is no base class (as in
the case of the object type) or if there is no base class
destructor, then the exception is discarded.
What is Assembly? Assemblies are the building blocks of .NET
Framework applications; they form the fundamental unit of
deployment, version control, reuse, activation scoping, and
security permissions. An assembly is a collection of types
and resources that are built to work together and form a
logical unit of functionality. An assembly provides the
common language runtime withthe information it needs to be
aware of type implementations. To the runtime, a type does
not exist outside the context of an assembly. Assemblies are
a fundamental part of programming withthe .NET Framework. An
assembly performs the following functions:
It contains code that the common language runtime executes.
Microsoft intermediate language (MSIL) code in a portable
executable (PE) file will not be executed if it does not
have an associated assembly manifest. Note that each
assembly can have only one entry point (that
is,DllMain,WinMain, orMain).
It forms asecurity boundary. An assembly is the unit at
which permissions are requested and granted.
It forms atype boundary. Every type’s identity includes the
name of the assembly in which it resides. A type called
MyType loaded in the scope of one assembly is not the same
as a type called MyType loaded in the scope of another
assembly.
It forms areference scope boundary. The assembly’s manifest
contains assembly metadata that is used for resolving types
and satisfying resource requests. It specifies the types and
resources that are exposed outside the assembly. The
manifest also enumerates other assemblies on which it
depends.
It forms aversion boundary. The assembly is the smallest
versionable unit in the common language runtime; all types
and resources in the same assembly are versioned as a unit.
The assembly’s manifest describes the version dependencies
you specify for any dependent assemblies.
It forms a deployment unit. When an application starts, only
the assemblies that the application initially calls must be
present. Other assemblies, such as localization resources or
assemblies containing utility classes, can be retrieved on
demand. This allows applications to be kept simple and thin
when first downloaded.
It is the unit at which side-by-side execution is supported.
Assemblies can be static or dynamic. Static assemblies can
include .NET Framework types (interfaces and classes), as
well as resources for the assembly (bitmaps, JPEG files,
resource files, and so on). Static assemblies are stored on
disk in PE files. You can also use the .NET Framework to
create dynamic assemblies, which are run directly from
memory and are not saved to disk before execution. You can
save dynamic assemblies to disk after they have executed.
There are several ways to create assemblies. You can use
development tools, such as Visual Studio .NET, that you have
used in the past to create .dll or .exe files. You can use
tools provided in the .NET Framework SDK to create
assemblies withmodules created in other development
environments. You can also use common language runtime APIs,
such as Reflection.Emit, to create dynamic assemblies.
s of assemblies? Private, Public/Shared, Satellite
What are Satellite Assemblies? How you will create this? How
will you get the different language strings? Satellite
assemblies are often used to deploy language-specific
resources for an application. These language-specific
assemblies work in side-by-side execution because the
application has a separate product ID for each language and
installs satellite assemblies in a language-specific
subdirectory for each language. When uninstalling, the
application removes only the satellite assemblies associated
witha given language and .NET Framework version. No core
.NET Framework files are removed unless the last language
for that .NET Framework version is being removed. For
example, English and Japanese editions of the .NET Framework
version 1.1 share the same core files. The Japanese .NET
Framework version 1.1 adds satellite assemblies
withlocalized resources in a \ja subdirectory. An
application that supports the .NET Framework version 1.1,
regardless of its language, always uses the same core
runtime files.
How will you load dynamic assembly? How will create
assemblies at run time?
What is Assembly manifest? what all details the assembly
manifest will contain. Every assembly, whether static or
dynamic, contains a collection of data that describes how
the elements in the assembly relate to each other. The
assembly manifest contains this assembly metadata. An
assembly manifest contains all the metadata needed to
specify the assembly’s version requirements and security
identity, and all metadata needed to define the scope of the
assembly and resolve references to resources and classes.
The assembly manifest can be stored in either a PE file (an
.exe or .dll) withMicrosoft intermediate language (MSIL)
code or in a standalone PE file that contains only assembly
manifest information. It contains Assembly name, Version
number, Culture, Strong name information, List of all files
in the assembly, Type reference information, Information on
referenced assemblies.
What are the contents of assembly? In general, a static
assembly can consist of four elements:
The assembly manifest, which contains assembly metadata.
Type metadata.
Microsoft intermediate language (MSIL) code that implements
the types.
A set of resources.
Difference between assembly manifest & metadata assembly
manifest -An integral part of every assembly that renders
the assembly self-describing. The assembly manifest contains
the assembly’s metadata. The manifest establishes the
assembly identity, specifies the files that make up the
assembly implementation, specifies the types and resources
that make up the assembly, itemizes the compile-time
dependencies on other assemblies, and specifies the set of
permissions required for the assembly to run properly. This
information is used at run time to resolve references,
enforce version binding policy, and validate the integrity
of loaded assemblies. The self-describing nature of
assemblies also helps makes zero-impact install and XCOPY
deployment feasible. metadata -Information that describes
every element managed by the common language runtime: an
assembly, loadable file, type, method, and so on. This can
include information required for debugging and garbage
collection, as well as security attributes, marshaling data,
extended class and member definitions, version binding, and
other information required by the runtime.
What is Global Assembly Cache (GAC) and what is the purpose
of it? (How to make an assembly to public? Steps) Each
computer where the common language runtime is installed has
a machine-wide code cache called the global assembly cache.
The global assembly cache stores assemblies specifically
designated to be shared by several applications on the
computer. You should share assemblies by installing them
into the global assembly cache only when you need to.
If I have more than one version of one assemblies, then
how’ll I use old version (how/where to specify version
number?)in my application?
How to find methods of a assembly file (not using ILDASM)
Reflection
Value type & data types difference. Example from .NET.
Integer & struct are value types or reference types in .NET?
What is Garbage Collection in .Net? Garbage collection
process? The process of transitively tracing through all
pointers to actively used objects in order to locate all
objects that can be referenced, and then arranging to reuse
any heap memory that was not found during this trace. The
common language runtime garbage collector also compacts the
memory that is in use to reduce the working space needed for
the heap.
Readonly vs. const? Aconstfield can only be initialized at
the declaration of the field. Areadonlyfield can be
initialized either at the declaration or in a constructor.
Therefore,readonlyfields can have different values depending
on the constructor used. Also, while aconstfield is a
compile-time constant, thereadonlyfield can be used for
runtime constants, as in the following example: public
static readonly uint l1 = (uint) DateTime.Now.Ticks;
//Declaring properties
public bool MyProperty
{
get {return this.myvalue;}
set {this.myvalue = value;}
}
ion to get access to custom attributes.
class MainClass
{
public static void Main()
{
System.Reflection.MemberInfo info = typeof(MyClass);
object[] attributes = info.GetCustomAttributes();
for (int i = 0; i < attributes.Length; i ++)
{
System.Console.WriteLine(attributes[i]);
}
}
}
C++ & C# differences
What is the managed and unmanaged code in .net? The .NET
Framework provides a run-time environment called the Common
Language Runtime, which manages the execution of code and
provides services that make the development process easier.
Compilers and tools expose the runtime’s functionality and
enable you to write code that benefits from this managed
execution environment. Code that you develop witha language
compiler that targets the runtime is calledmanaged code;
itbenefits from features such as cross-language integration,
cross-language exception handling, enhanced security,
versioning and deployment support, a simplified model for
component interaction, and debugging and profiling services.
How do you create threading in .NET? What is the namespace
for that?
using directive vs using statement You create an instance in
ausingstatement to ensure thatDispose is called on the
object when theusingstatement is exited. Ausing statement
can be exited either when the end of theusingstatement is
reached or if, for example, an exception is thrown and
control leaves the statement block before the end of the
statement. The using directive has two uses.
Create an alias for a namespace (a using alias).
Permit the use of types in a namespace, such that, you do
not have to qualify the use of a type in that namespace (ausingdirective).
Describe the Managed Execution Process
What is Active Directory? What is the namespace used to
access the Microsoft Active Directories?
Interop Services?
What is RCW (Run time Callable Wrappers)? The common
language runtime exposes COM objects through a proxy called
the runtime callable wrapper (RCW). Although the RCW appears
to be an ordinary object to .NET clients, its primary
function is to marshal calls between a .NET client and a COM
object.
What is CCW (COM Callable Wrapper)
A proxy object generated by the common language runtime so
that existing COM applications can use managed classes,
including .NET Framework classes, transparently.
How does you handle this COM components developed in other
programming languages in .NET?
How will you register com+ services?
What is use of ContextUtil class? ContextUtil is the
preferred class to use for obtaining COM+ context
information.
What is the new three features of COM+ services, which are
not there in COM (MTS)
Is the COM architecture same as .Net architecture? What is
the difference between them (if at all there is)? |
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