1. What is .NET Framework?
The .NET Framework has two main components: the common language runtime and
the .NET Framework class library.
You can think of the runtime as an agent that manages code at execution time,
providing core services such as memory management, thread management, and
remoting, while also enforcing strict type safety and other forms of code accuracy that
ensure security and robustness.
The class library, is a comprehensive, object-oriented collection of reusable types that
you can use to develop applications ranging from traditional command-line or
graphical user interface (GUI) applications to applications based on the latest
innovations provided by ASP.NET, such as Web Forms and XML Web services.
2. What is CLR?
The CLS is simply a specification that defines the rules to support language integration
in such a way that programs written in any language, yet can interoperate with one
another, taking full advantage of inheritance, polymorphism, exceptions, and other
features. These rules and the specification are documented in the ECMA proposed
standard document, "Partition I Architecture", available here.
3. Is .NET a runtime service or a development platform?
Ans: It's both and actually a lot more. Microsoft .NET includes a new way of delivering
software and services to businesses and consumers. A part of Microsoft.NET is the
.NET Frameworks. The .NET frameworks SDK consists of two parts: the .NET common
language runtime and the .NET class library. 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.
4. What are the new features of Framework 1.1 ?
1. Native Support for Developing Mobile Web Applications
2. Enable Execution of Windows Forms Assemblies Originating from the Internet
Assemblies originating from the Internet zone—for example, Microsoft
Windows® Forms controls embedded in an Internet-based Web page or
Windows Forms assemblies hosted on an Internet Web server and loaded
either through the Web browser or programmatically using the
System.Reflection.Assembly.LoadFrom() method—now receive sufficient
permission to execute in a semi-trusted manner. Default security policy has
been changed so that assemblies assigned by the common language runtime
(CLR) to the Internet zone code group now receive the constrained
permissions associated with the Internet permission set. In the .NET
Framework 1.0 Service Pack 1 and Service Pack 2, such applications received
the permissions associated with the Nothing permission set and could not
execute.
3. Enable Code Access Security for ASP.NET Applications
Systems administrators can now use code access security to further lock down
the permissions granted to ASP.NET Web applications and Web services.
Although the operating system account under which an application runs
imposes security restrictions on the application, the code access security
system of the CLR can enforce additional restrictions on selected application
resources based on policies specified by systems administrators. You can use
this feature in a shared server environment (such as an Internet service
provider (ISP) hosting multiple Web applications on one server) to isolate
separate applications from one another, as well as with stand-alone servers
where you want applications to run with the minimum necessary privileges.
4. Native Support for Communicating with ODBC and Oracle Databases
5. Unified Programming Model for Smart Client Application Development
The Microsoft .NET Compact Framework brings the CLR, Windows Forms
controls, and other .NET Framework features to small devices. The .NET
Compact Framework supports a large subset of the .NET Framework class
library optimized for small devices.
6. Support for IPv6
The .NET Framework 1.1 supports the emerging update to the Internet
Protocol, commonly referred to as IP version 6, or simply IPv6. This protocol is
designed to significantly increase the address space used to identify
communication endpoints in the Internet to accommodate its ongoing growth.
5. What is Code Access Security (CAS)?
CAS is the part of the .NET security model that determines whether or not a piece of
code is allowed to run, and what resources it can use when it is running. For example,
it is CAS that will prevent a .NET web applet from formatting your hard disk.
How does CAS work?
The CAS security policy revolves around two key concepts - code groups and
permissions. Each .NET assembly is a member of a particular code group, and each
code group is granted the permissions specified in a named permission set.
For example, using the default security policy, a control downloaded from a web site
belongs to the 'Zone - Internet' code group, which adheres to the permissions defined
by the 'Internet' named permission set. (Naturally the 'Internet' named permission set
represents a very restrictive range of permissions.)
Who defines the CAS code groups?
Microsoft defines some default ones, but you can modify these and even create your
own. To see the code groups defined on your system, run 'caspol -lg' from the
command-line. On my ssystem it looks like this:
6. Level = Machine
7. Code Groups:
8.
9. 1. All code: Nothing
10. 1.1. Zone - MyComputer: FullTrust
11. 1.1.1. Honor SkipVerification requests: SkipVerification
12. 1.2. Zone - Intranet: LocalIntranet
13. 1.3. Zone - Internet: Internet
14. 1.4. Zone - Untrusted: Nothing
15. 1.5. Zone - Trusted: Internet
16. 1.6. StrongName -
0024000004800000940000000602000000240000525341310004000003
17. 000000CFCB3291AA715FE99D40D49040336F9056D7886FED46775BC7BB5430BA444
4FEF8348EBD06
18. F962F39776AE4DC3B7B04A7FE6F49F25F740423EBF2C0B89698D8D08AC48D69CED0
FC8F83B465E08
19. 07AC11EC1DCC7D054E807A43336DDE408A5393A48556123272CEEEE72F1660B7192
7D38561AABF5C
AC1DF1734633C602F8F2D5: Everything
Note the hierarchy of code groups - the top of the hierarchy is the most general ('All
code'), which is then sub-divided into several groups, each of which in turn can be
sub-divided. Also note that (somewhat counter-intuitively) a sub-group can be
associated with a more permissive permission set than its parent.
How do I define my own code group?
Use caspol. For example, suppose you trust code from www.mydomain.com and you
want it have full access to your system, but you want to keep the default restrictions
for all other internet sites. To achieve this, you would add a new code group as a subgroup
of the 'Zone - Internet' group, like this:
caspol -ag 1.3 -site www.mydomain.com FullTrust
Now if you run caspol -lg you will see that the new group has been added as group
1.3.1:
...
1.3. Zone - Internet: Internet
1.3.1. Site - www.mydomain.com: FullTrust
...
Note that the numeric label (1.3.1) is just a caspol invention to make the code groups
easy to manipulate from the command-line. The underlying runtime never sees it.
How do I change the permission set for a code group?
Use caspol. If you are the machine administrator, you can operate at the 'machine'
level - which means not only that the changes you make become the default for the
machine, but also that users cannot change the permissions to be more permissive. If
you are a normal (non-admin) user you can still modify the permissions, but only to
make them more restrictive. For example, to allow intranet code to do what it likes
you might do this:
caspol -cg 1.2 FullTrust
Note that because this is more permissive than the default policy (on a standard
system), you should only do this at the machine level - doing it at the user level will
have no effect.
Can I create my own permission set?
Yes. Use caspol -ap, specifying an XML file containing the permissions in the
permission set. To save you some time, here is a sample file corresponding to the
'Everything' permission set - just edit to suit your needs. When you have edited the
sample, add it to the range of available permission sets like this:
caspol -ap samplepermset.xml
Then, to apply the permission set to a code group, do something like this:
caspol -cg 1.3 SamplePermSet (By default, 1.3 is the 'Internet' code group)
I'm having some trouble with CAS. How can I diagnose my problem?
Caspol has a couple of options that might help. First, you can ask caspol to tell you
what code group an assembly belongs to, using caspol -rsg. Similarly, you can ask
what permissions are being applied to a particular assembly using caspol -rsp.
I can't be bothered with all this CAS stuff. Can I turn it off?
Yes, as long as you are an administrator. Just run:
caspol -s off
20. What is MSIL, IL?
When compiling to managed code, the compiler translates your source code into
Microsoft intermediate language (MSIL), which is a CPU-independent set of
instructions that can be efficiently converted to native code. MSIL includes instructions
for loading, storing, initializing, and calling methods on objects, as well as instructions
for arithmetic and logical operations, control flow, direct memory access, exception
handling, and other operations. Microsoft intermediate language (MSIL) is a language
used as the output of a number of compilers and as the input to a just-in-time (JIT)
compiler. The common language runtime includes a JIT compiler for converting MSIL
to native code.
21. Can I write IL programs directly?
Yes. Peter Drayton posted this simple example to the DOTNET mailing list:
.assembly MyAssembly {}
.class MyApp {
.method static void Main() {
.entrypoint
ldstr "Hello, IL!"
call void System.Console::WriteLine(class System.Object)
ret
}
}
Just put this into a file called hello.il, and then run ilasm hello.il. An exe assembly will
be generated.
Can I do things in IL that I can't do in C#?
Yes. A couple of simple examples are that you can throw exceptions that are not
derived from System.Exception, and you can have non-zero-based arrays.
22. What is CTS?
The common type system defines how types are declared, used, and managed in the
runtime, and is also an important part of the runtime's support for cross-language
integration.
The common type system supports two general categories of types, each of which is
further divided into subcategories:
Value types
Value types directly contain their data, and instances of value types are either
allocated on the stack or allocated inline in a structure. Value types can be
built-in (implemented by the runtime), user-defined, or enumerations.
Reference types
Reference types store a reference to the value's memory address, and are
allocated on the heap. Reference types can be self-describing types, pointer
types, or interface types. The type of a reference type can be determined from
values of self-describing types. Self-describing types are further split into
arrays and class types. The class types are user-defined classes, boxed value
types, and delegates.
2. What is JIT (just in time)? how it works?
Before Microsoft intermediate language (MSIL) can be executed, it must be
converted by a .NET Framework just-in-time (JIT) compiler to native code,
which is CPU-specific code that runs on the same computer architecture as the
JIT compiler.
Rather than using time and memory to convert all the MSIL in a portable
executable (PE) file to native code, it converts the MSIL as it is needed during
execution and stores the resulting native code so that it is accessible for
subsequent calls.
The runtime supplies another mode of compilation called install-time code
generation. The install-time code generation mode converts MSIL to native
code just as the regular JIT compiler does, but it converts larger units of code
at a time, storing the resulting native code for use when the assembly is
subsequently loaded and executed.
As part of compiling MSIL to native code, code must pass a verification process
unless an administrator has established a security policy that allows code to
bypass verification. Verification examines MSIL and metadata to find out
whether the code can be determined to be type safe, which means that it is
known to access only the memory locations it is authorized to access.
3. 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.
4. 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
5. Which namespace is the base class for .net Class library?
Ans: system.object
6. What is Event - Delegate? clear syntax for writing a event delegate
The event keyword lets you specify a delegate that will be called upon the
occurrence of some "event" in your code. The delegate can have one or more
associated methods that will be called when your code indicates that the event
has occurred. An event in one program can be made available to other
programs that target the .NET Framework Common Language Runtime.
// keyword_delegate.cs
// delegate declaration
delegate void MyDelegate(int i);
7. class Program
8. {
9. public static void Main()
10. {
11. TakesADelegate(new MyDelegate(DelegateFunction));
12. }
13. public static void TakesADelegate(MyDelegate SomeFunction)
14. {
15. SomeFunction(21);
16. }
17. public static void DelegateFunction(int i)
18. {
19. System.Console.WriteLine("Called by delegate with number: {0}.", i);
20. }
}
21. What are object pooling and connection pooling and difference? Where
do we set the Min and Max Pool size for connection pooling?
Object pooling is a COM+ service that enables you to reduce the overhead of
creating each object from scratch. When an object is activated, it is pulled
from the pool. When the object is deactivated, it is placed back into the pool to
await the next request. You can configure object pooling by applying the
ObjectPoolingAttribute attribute to a class that derives from the
System.EnterpriseServices.ServicedComponent class.
Object pooling lets you control the number of connections you use, as opposed
to connection pooling, where you control the maximum number reached.
Following are important differences between object pooling and connection
pooling:
Creation. When using connection pooling, creation is on the same thread, so
if there is nothing in the pool, a connection is created on your behalf. With
object pooling, the pool might decide to create a new object. However, if you
have already reached your maximum, it instead gives you the next available
object. This is crucial behavior when it takes a long time to create an object,
but you do not use it for very long.
Enforcement of minimums and maximums. This is not done in connection
pooling. The maximum value in object pooling is very important when trying to
scale your application. You might need to multiplex thousands of requests to
just a few objects. (TPC/C benchmarks rely on this.)
COM+ object pooling is identical to what is used in .NET Framework managed SQL
Client connection pooling. For example, creation is on a different thread and
minimums and maximums are enforced.
22. What is Application Domain?
The primary purpose of the AppDomain is to isolate an application from other
applications. Win32 processes provide isolation by having distinct memory
address spaces. This is effective, but it is expensive and doesn't scale well. The
.NET runtime enforces AppDomain isolation by keeping control over the use of
memory - all memory in the AppDomain is managed by the .NET runtime, so
the runtime can ensure that AppDomains do not access each other's memory.
Objects in different application domains communicate either by transporting
copies of objects across application domain boundaries, or by using a proxy to
exchange messages.
MarshalByRefObject is the base class for objects that communicate across
application domain boundaries by exchanging messages using a proxy. Objects
that do not inherit from MarshalByRefObject are implicitly marshal by value.
When a remote application references a marshal by value object, a copy of the
object is passed across application domain boundaries.
How does an AppDomain get created?
AppDomains are usually created by hosts. Examples of hosts are the Windows Shell,
ASP.NET and IE. When you run a .NET application from the command-line, the host is
the Shell. The Shell creates a new AppDomain for every application.
AppDomains can also be explicitly created by .NET applications. Here is a C# sample
which creates an AppDomain, creates an instance of an object inside it, and then
executes one of the object's methods. Note that you must name the executable
'appdomaintest.exe' for this code to work as-is.
using System;
using System.Runtime.Remoting;
public class CAppDomainInfo : MarshalByRefObject
{
public string GetAppDomainInfo()
{
return "AppDomain = " + AppDomain.CurrentDomain.FriendlyName;
}
}
public class App
{
public static int Main()
{
AppDomain ad = AppDomain.CreateDomain( "Andy's new domain", null,
null );
ObjectHandle oh = ad.CreateInstance( "appdomaintest",
"CAppDomainInfo" );
CAppDomainInfo adInfo = (CAppDomainInfo)(oh.Unwrap());
string info = adInfo.GetAppDomainInfo();
Console.WriteLine( "AppDomain info: " + info );
return 0;
}
}
23. What is serialization in .NET? What are the ways to control
serialization?
Serialization is the process of converting an object into a stream of bytes.
Deserialization is the opposite process of creating an object from a stream of
bytes. Serialization/Deserialization is mostly used to transport objects (e.g.
during remoting), or to persist objects (e.g. to a file or database).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.
There are two separate mechanisms provided by the .NET class library - XmlSerializer
and SoapFormatter/BinaryFormatter. Microsoft uses XmlSerializer for Web Services,
and uses SoapFormatter/BinaryFormatter for remoting. Both are available for use in
your own code.
Why do I get errors when I try to serialize a Hashtable?
XmlSerializer will refuse to serialize instances of any class that implements IDictionary,
e.g. Hashtable. SoapFormatter and BinaryFormatter do not have this restriction.
25. What are server controls?
ASP.NET server controls are components that run on the server and
encapsulate user-interface and other related functionality. They are used in
ASP.NET pages and in ASP.NET code-behind classes.
26. What is the difference between Web User Control and Web Custom
Control?
Custom Controls
Web custom controls are compiled components that run on the server and that
encapsulate user-interface and other related functionality into reusable
packages. They can include all the design-time features of standard ASP.NET
server controls, including full support for Visual Studio design features such as
the Properties window, the visual designer, and the Toolbox.
There are several ways that you can create Web custom controls:
You can compile a control that combines the functionality of two or more
existing controls. For example, if you need a control that encapsulates a
button and a text box, you can create it by compiling the existing controls
together.
If an existing server control almost meets your requirements but lacks some
required features, you can customize the control by deriving from it and
overriding its properties, methods, and events.
If none of the existing Web server controls (or their combinations) meet your
requirements, you can create a custom control by deriving from one of the
base control classes. These classes provide all the basic functionality of Web
server controls, so you can focus on programming the features you need.
If none of the existing ASP.NET server controls meet the specific requirements of your
applications, you can create either a Web user control or a Web custom control that
encapsulates the functionality you need. The main difference between the two controls
lies in ease of creation vs. ease of use at design time.
Web user controls are easy to make, but they can be less convenient to use in
advanced scenarios. You develop Web user controls almost exactly the same way that
you develop Web Forms pages. Like Web Forms, user controls can be created in the
visual designer, they can be written with code separated from the HTML, and they can
handle execution events. However, because Web user controls are compiled
dynamically at run time they cannot be added to the Toolbox, and they are
represented by a simple placeholder glyph when added to a page. This makes Web
user controls harder to use if you are accustomed to full Visual Studio .NET designtime
support, including the Properties window and Design view previews. Also, the
only way to share the user control between applications is to put a separate copy in
each application, which takes more maintenance if you make changes to the control.
Web custom controls are compiled code, which makes them easier to use but more
difficult to create; Web custom controls must be authored in code. Once you have
created the control, however, you can add it to the Toolbox and display it in a visual
designer with full Properties window support and all the other design-time features of
ASP.NET server controls. In addition, you can install a single copy of the Web custom
control in the global assembly cache and share it between applications, which makes
maintenance easier.
Web user controls Web custom controls
Easier to create Harder to create
Limited support for consumers who use a
visual design tool
Full visual design tool support for consumers
A separate copy of the control is required
in each application
Only a single copy of the control is required,
in the global assembly cache
Cannot be added to the Toolbox in Visual
Studio
Can be added to the Toolbox in Visual Studio
Good for static layout Good for dynamic layout
27. 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 with try statements more nested that than the one that caught the
exception.
Exceptions that occur during destructor execution are worth special 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.
28. 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 with the 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 with the .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, or
Main).
It forms a security boundary. An assembly is the unit at which permissions are
requested and granted.
It forms a type 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 a reference 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 a version 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 with modules
created in other development environments. You can also use common language
runtime APIs, such as Reflection.Emit, to create dynamic assemblies.
29. 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.
30. What are the different types of assemblies?
Private, Public/Shared, Satellite
31. What is the difference between a private assembly and a shared
assembly?
1. Location and visibility: A private assembly is normally used by a single
application, and is stored in the application's directory, or a sub-directory
beneath. A shared assembly is normally stored in the global assembly cache,
which is a repository of assemblies maintained by the .NET runtime. Shared
assemblies are usually libraries of code which many applications will find
useful, e.g. the .NET framework classes.
2. Versioning: The runtime enforces versioning constraints only on shared
assemblies, not on private assemblies.
23. 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 with a 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 with localized 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.)
24. How will u load dynamic assembly? How will create assemblies at run
time?
**
25. 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) with
Microsoft 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.
26. 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.
27. What is Global Assembly Cache (GAC) and what is the purpose of it?
(How to make an assembly to public? Steps) How more than one
version of an assembly can keep in same place?
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.
Steps
- Create a strong name using sn.exe tool
eg: sn -k keyPair.snk
- with in AssemblyInfo.cs add the generated file name
eg: [assembly: AssemblyKeyFile("abc.snk")]
- recompile project, then install it to GAC by either
drag & drop it to assembly folder (C:\WINDOWS\assembly OR
C:\WINNT\assembly) (shfusion.dll tool)
or
gacutil -i abc.dll
28. 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?
**
29. How to find methods of a assembly file (not using ILDASM)
Reflection
30. 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.
31. Readonly vs. const?
A const field can only be initialized at the declaration of the field. A readonly
field can be initialized either at the declaration or in a constructor. Therefore,
readonly fields can have different values depending on the constructor used.
Also, while a const field is a compile-time constant, the readonly field can be
used for runtime constants, as in the following example:
public static readonly uint l1 = (uint) DateTime.Now.Ticks;
32. What is Reflection in .NET? Namespace? How will you load an
assembly which is not referenced by current assembly?
All .NET compilers produce metadata about the types defined in the modules
they produce. This metadata is packaged along with the module (modules in
turn are packaged together in assemblies), and can be accessed by a
mechanism called reflection. The System.Reflection namespace contains
classes that can be used to interrogate the types for a module/assembly.
Using reflection to access .NET metadata is very similar to using
ITypeLib/ITypeInfo to access type library data in COM, and it is used for similar
purposes - e.g. determining data type sizes for marshaling data across
context/process/machine boundaries.
Reflection can also be used to dynamically invoke methods (see
System.Type.InvokeMember), or even create types dynamically at run-time
(see System.Reflection.Emit.TypeBuilder).
