The .NET Framework has two main components: the common language runtime and the .NET Framework class library.
common language runtime
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 .NET Framework provides a runtime environment called the Common Language Runtime or CLR (similar to the Java Virtual Machine or JVM in Java), which handles the execution of code and provides useful services for the implementation of the program. CLR takes care of code management at program execution and provides various beneficial services such as memory management, thread management, security management, code verification, compilation, and other system services. The managed code that targets CLR benefits from useful features such as cross-language integration, cross-language exception handling, versioning, enhanced security, deployment support, and debugging.
class library
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.
Common Type System
Common Type System (CTS) describes how types are declared, used and managed in the runtime and facilitates cross-language integration, type safety, and high performance code execution.
Common Language Specification
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",
When was the first version of .NET released?
The final version of the 1.0 SDK and runtime was made publicly available around 6pm PST on 15-Jan-2002. At the same time, the final version of Visual Studio.NET was made available to MSDN subscribers.
What platforms does the .NET Framework run on?
The runtime supports Windows XP, Windows 2000, NT4 SP6a and Windows ME/98. Windows 95 is not supported. Some parts of the framework do not work on all platforms - for example, ASP.NET is only supported on Windows XP and Windows 2000. Windows 98/ME cannot be used for development.
IIS is not supported on Windows XP Home Edition, and so cannot be used to host ASP.NET. However, the ASP.NET Web Matrix web server does run on XP Home.
The Mono project is attempting to implement the .NET framework on Linux.
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 with a language compiler that targets the runtime is called managed code; it benefits 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.
Differnce between Managed code and unmanaged code ?
Managed Code:
Code that runs under a "contract of cooperation" with the common language runtime. Managed code must supply the metadata necessary for the runtime to provide services such as memory management, cross-language integration, code access security, and
automatic lifetime control of objects. All code based on Microsoft intermediate language (MSIL) executes as managed code.
Un-Managed Code:
Code that is created without regard for the conventions and requirements of the common language runtime. Unmanaged code executes in the common language runtime environment with minimal services (for example, no garbage collection, limited debugging, and so on).
Describe the Managed Execution Process?
The managed execution process includes the following steps:
Choosing a compiler.
To obtain the benefits provided by the common language runtime, you must use one or more language compilers that target the runtime.
Compiling your code to Microsoft intermediate language (MSIL).
Compiling translates your source code into MSIL and generates the required metadata.
Compiling MSIL to native code.
At execution time, a just-in-time (JIT) compiler translates the MSIL into native code. During this compilation, code must pass a verification process that examines the MSIL and metadata to find out whether the code can be determined to be type safe.
Executing your code.
The common language runtime provides the infrastructure that enables execution to take place as well as a variety of services that can be used during execution.
What is a CLR host?
The Windows operating system does not provide support for running a CLR application. That support is provided by a CLR host. A CLR host is an application that is responsible for loading the CLR into a process, creating application domains within the process, and executing user code within the application domains. Examples of hosts that ship with the .NET Framework include:
ASP.NET. An ISAPI filter [Internet Server Application Programming Interface] that ships with ASP.NET loads the CLR and does the initialization necessary to handle web requests.
Internet Explorer. A MIME filter [Multipurpose Internet Mail Extensions] hooks into Internet Explorer versions 5.01 and higher to execute managed controls referenced from HTML pages.
Shell Executables. When a managed application is launched from a shell, a small piece of unmanaged code loads the CLR and transitions control of the application to the CLR.
Hosting the Common Language Runtime. Describes how to load the Common Language Runtime into a process, define the application domains within the process, and execute user code within those application domains.
Managed Code
Code that you develop with a language compiler that targets the runtime is called managed code
The Code that developed with .net language compiler for .net framework futures 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 will target the CLR for exection which is called as managed code.
How do I run managed code in a process?
The first step in running managed code in a process is to get the CLR loaded and initialized using a CLR host. Typically, a host consists of both managed code and unmanaged code. The managed code which executes in the default domain is usually responsible for creating the application domains in which the user code exists. All CLR hosts must contain unmanaged code because execution must begin in unmanaged code. The .NET Frameworks provides a set of unmanaged APIs that the host can use to configure the CLR, load the CLR into a process, load the hosts managed code into the default domain, and transition from the unmanaged code to the managed code.
The second step in running managed code in a process is to create application domains in which the user code will execute. The creator of the application domain can specify criteria which control code isolation, security, and loading of assemblies.
The third step in running managed code in a process is to execute user code in one or more application domains created in the previous step. All code that is run in the CLR must be part of an assembly.
There are three options for loading assemblies.
First, precompiled assemblies can be loaded from disk.
Second, precompiled assemblies can be loaded from an array of bytes.
Third, assemblies can be built dynamically in an application domain using the BCL Reflection Emit APIs.
Note. For an application launched from the command-line, the shell host executes the steps described above on behalf of the user and hides the complexity from the user.
For more information see Hosting the Common Language Runtime.
What is JIT and how is works ?
An acronym for "just-in-time," a phrase that describes an action that is taken only when it becomes necessary, such as just-in-time compilation or just-in-time object activation
What is portable executable (PE) ?
The file format used for executable programs and for files to be linked together to form executable programs
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 [Internet Protocol Version 6]
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.
http://msdn.microsoft.com/netframework/technologyinfo/Overview/whatsnew.aspx
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.
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.
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.
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.
What is MSIL?.
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. Before code can be run, MSIL must be converted to CPU-specific code, usually by a just-in-time (JIT) compiler. Because the common language runtime supplies one or more JIT compilers for each computer architecture it supports, the same set of MSIL can be JIT-compiled and run on any supported architecture.
When a compiler produces MSIL, it also produces metadata. Metadata describes the types in your code, including the definition of each type, the signatures of each type's members, the members that your code references, and other data that the runtime uses at execution time. The MSIL and metadata are contained in a portable executable (PE) file that is based on and extends the published Microsoft PE and common object file format (COFF) used historically for executable content. This file format, which accommodates MSIL or native code as well as metadata, enables the operating system to recognize common language runtime images. The presence of metadata in the file along with the MSIL enables your code to describe itself, which means that there is no need for type libraries or Interface Definition Language (IDL). The runtime locates and extracts the metadata from the file as needed during execution.
What is Jit compilers?.how many are available in clr?
Just-In-Time compiler- it converts the language that you write in .Net into machine language that a computer can understand. There are two types of JITs one is memory optimized & other is performace optimized.
What type of code (server or client) is found in a Code-Behind class?
Server
What is MSIL, IL, CTS and, CLR ?
MSIL: (Microsoft intermediate language)
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. Before code can be executed, MSIL must be converted to CPU-specific code, usually by a just-in-time (JIT) compiler. Because the common language runtime supplies one or more JIT compilers for each computer architecture it supports, the same set of MSIL can be JIT-compiled and executed on any supported architecture.
When a compiler produces MSIL, it also produces metadata. Metadata describes the types in your code, including the definition of
each type, the signatures of each type's members, the members that your code references, and other data that the runtime uses at
execution time. The MSIL and metadata are contained in a portable executable (PE) file that is based on and extends the published
Microsoft PE and Common Object File Format (COFF) used historically for executable content. This file format, which accommodates
MSIL or native code as well as metadata, enables the operating system to recognize common language runtime images. The
presence of metadata in the file along with the MSIL enables your code to describe itself, which means that there is no need for type libraries or Interface Definition Language (IDL). The runtime locates and extracts the metadata from the file as needed during
execution.
IL: (Intermediate Language)
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.
CTS: (Common Type System)
The specification that determines how the common language runtime defines, uses, and manages types
CLR: (Common Language Runtime)
The engine at the core of managed code execution. The runtime supplies managed code with services such as cross-language integration, code access security, object lifetime management, and debugging and profiling support.
What is meant by language interoperability and language integration?
Prior to the introduction of .Net, the code written in one programming language is considered to be usable only in the programs written with the same programming languages. For example, an algorithm implemented in Perl programming language can not be reused in the programs written in the C++. At Windows platform, Microsoft introduced the standards for COM (Component Object Model) which allows components written in one programming language to be used in other programming language. In Java, JNI (Java Native Interface) is presented to use-up the code written in non-Java languages into Java programs. But both the standards (COM and JNI) are too complex and have their own limitations. They also don’t allow the language integration, which means that you can use the components written in other programming languages but you can’t extend the functionality of the components.
In Microsoft.Net, the code written in any programming language is compiled to the same Intermediate Language (Microsoft Intermediate Language - MSIL or Common Intermediate Language – CIL) and to same component standard (assembly). Hence, it is possible for developers to employ the language interoperability by using and extending the solution implemented by other developers which might be using different programming language provided developers at both end are using.Net compliant programming languages.
What is reflection?
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).
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).
What is Partial Assembly References?
Full Assembly reference: A full assembly reference includes the assembly's text name, version, culture, and public key token (if the assembly has a strong name). A full assembly reference is required if you reference any assembly that is part of the common
language runtime or any assembly located in the global assembly cache.
Partial Assembly reference: We can dynamically reference an assembly by providing only partial information, such as specifying only the assembly name. When you specify a partial assembly reference, the runtime looks for the assembly only in the application directory.
We can make partial references to an assembly in your code one of the following ways:
-> Use a method such as System.Reflection.Assembly.Load and specify only a partial reference. The runtime checks for the assembly in the application directory.
-> Use the System.Reflection.Assembly.LoadWithPartialName method and specify only a partial reference. The runtime checks for the assembly in the application directory and in the global assembly cache
What is Machine.config?
Machine configuration file: The machine.config file contains settings that apply to the entire computer. This file is located in the %runtime install path%Config directory. There is only one ...
passwordFormat="[Clear|SHA1|MD5]"
Member name Description
Clear Specifies that passwords are not encrypted.
MD5 Specifies that passwords are encrypted using the MD5 hash algorithm.
SHA1 Specifies that passwords are encrypted using the SHA1 hash algorithm.
What is Web.config?
ASP.NET configuration files are XML-based text files. Each "web.config" file applies configuration settings to the directory it is located in and to all virtual sub directories under it.
Settings in sub directories can optionally override or modify settings specified in main directories. The root configuration file "WinNT\Microsoft.NET\Framework\
In classic ASP all Web site related information was stored in the metadata of IIS. This had the disadvantage that remote Web developers couldn't easily make Web-site configuration changes. For that in Web.config file we can store the metadata.
Which namespace is the base class for .net Class library?
Ans: system.object
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.
What is Custom attribute? How to create? If I'm having custom attribute in an assembly, how to say that name in the code?
A: The primary steps to properly design custom attribute classes are as follows:
. Applying the AttributeUsageAttribute ([AttributeUsage(AttributeTargets.All, Inherited = false, AllowMultiple = true)])
a. Declaring the attribute. (class public class MyAttribute : System.Attribute { // . . . })
b. Declaring constructors (public MyAttribute(bool myvalue) { this.myvalue = myvalue; })
c. Declaring properties
public bool MyProperty
{
get {return this.myvalue;}
set {this.myvalue = value;}
}
The following example demonstrates the basic way of using reflection 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]);
}
}
}
How do you create threading in .NET? What is the namespace for that?
System.Threading.Thread
What is nmake tool?
The Nmake tool (Nmake.exe) is a 32-bit tool that you use to build projects based on commands contained in a .mak file.
usage : nmake -a all
What are Namespaces?
The namespace keyword is used to declare a scope. This namespace scope lets you organize code and gives you a way to create globally-unique types. Even if you do not explicitly declare one, a default namespace is created. This unnamed namespace, sometimes called the global namespace, is present in every file. Any identifier in the global namespace is available for use in a named namespace. Namespaces implicitly have public access and this is not modifiable.
What are indexers?
Indexers are similar to properties, except that the get and set accessors of indexers take parameters, while property accessors do not.
Defining an indexer allows you to create classes that act like "virtual arrays." Instances of that class can be accessed using the [] array access operator. Defining an indexer in C# is similar to defining operator [] in C++, but is considerably more flexible. For classes that encapsulate array- or collection-like functionality, using an indexer allows the users of that class to use the array syntax to access the class.
Example
The following example shows how to declare a private array field, myArray, and an indexer. Using the indexer allows direct access to the instance b[i]. The alternative to using the indexer is to declare the array as a public member and access its members, myArray[i], directly.
// cs_keyword_indexers.cs
using System;
class IndexerClass
{
private int [] myArray = new int[100];
public int this [int index] // Indexer declaration
{
get
{
// Check the index limits.
if (index <>= 100)
return 0;
else
return myArray[index];
}
set
{
if (!(index <>= 100))
myArray[index] = value;
}
}
}
public class MainClass
{
public static void Main()
{
IndexerClass b = new IndexerClass();
// Call the indexer to initialize the elements #3 and #5.
b[3] = 256;
b[5] = 1024;
for (int i=0; i<=10; i++)
{
Console.WriteLine("Element #{0} = {1}", i, b[i]);
}
}
}
how dot net compiled code will become platform independent?
Many people ask this question "Java is platform independent, what about .NET ?".
The answer is "Yes" and "No" !
The code you write is platform independent, because whatever you write is getting compiled into MSIL. There is no native code, which depends on your operating system or CPU. But when you execute the MSIL, the .NET framework in the target system will convert the MSIL into native platform code.
So, if you run your .NET exe in a WIndows machine, the .NET framework for Windows will convert it into Windows native code and execute. If you run your .NET application in Unix or Linux, the .NET framework for Unix/Linux will convert your code into Unix/Linux native code and execute. So, your code is purely platform independent and runs anywhere!
But wait, we said it wrong... there is no .NET framework for Unix or Linux available now. Microsoft has written the .NET framework only for Windows. If you or some one else write a .NET framework for other platforms in future, your code will run there too. So, let us wait until someone write .NET framework for Linux before you run your .NET code in Linux.
without modifying source code if we compile again, will it be generated MSIL again?
Yes
You will get message every time when you compiling
Build complete -- 0 errors, 3 warnings
Building satellite assemblies...
Performing Post-Build Event...
1 file(s) copied.
Where would you use an iHTTPModule, and what are the limitations of anyapproach you might take in implementing one?
One of ASP.NET’s most useful features is the extensibility of the HTTP pipeline, the path that data takes between client and server. You can use them to extend your ASP.NET applications by adding pre- and post-processing to each HTTP request coming into your application. For example, if you wanted custom authentication facilities for your application, the best technique would be to intercept the request when it comes in and process the request in a custom HTTP module.
What is the difference between "using System.Data;" and directly adding the reference from "Add References Dialog Box"?
When u compile a program using command line, u add the references using /r switch. When you compile a program using Visual Studio, it adds those references to our assembly, which are added us...
How is a property designated as read-only?
Public ReadOnly Property PropertyName As ReturnType
Get ‘Your Property Implementation goes in here
End Get
End Propertyin C#
public returntype PropertyName
{
get{
//property implementation goes here
}
// Do not write the set implementation
}
What are the shortcomings of MS.NET platform?
The foremost short coming of .NET platform is that it is still the propriety of Microsoft. It is more coupled with the Microsoft Windows operating system and is implemented only on Microsoft Windows successfully. MS.NET desktop applications can run only on Microsoft Windows,
Web based applications and web services can only be deployed on Microsoft Internet Information Server (IIS).
Since, dot net framework contains a lot of utilities, components, and framework class libraries, the size of downloadable framework is quite large (25MB compared to 5MB size of JVM).
Not all types of applications can be written in .NET managed applications, for example, you can’t write CLR or Operating System in your managed applications.
The managed .Net applications are somewhat slower to start and run than the traditional Win32 applications. The compiled code of .Net managed applications is easier to de-compile back to the source code.
What is Active Directory? What namespace should I use to use Active Directories?
Active Directory Service Interfaces (ADSI) is a programmatic interface for the Microsoft Windows Active Directory. It enables your applications to interact with different directories on a network using a single interface.
Visual Studio .NET and the .NET Framework make it easy to add ADSI functionality with the DirectoryEntry and DirectorySearcher components. Using ADSI you can create applications that perform common administrative tasks, such as backing up databases, accessing printers and managing user accounts. ADSI allows:
1) Log on once to work with diverse directories. The DirectoryEntry component class provides username and password properties that can be entered at Runtime and are passed to the Active Directory object you are bound to.
2) Use of an Application-Programming Interface (API) to perform tasks on multiple directory systems. This includes multi protocol support. The DirectoryServices namespace provides the classes to perform most administrative functions such as creating users.
3) Perform "Rich Querying" on directory systems. ADSI technology supports searching for objects with two query dialects: SQL and LDAP.
4) Access and use a single or hierarchical tree structure for administering and maintaining a diverse and complicated network.
5) Integrate directory information with databases such as ?SQL Server. The DirectoryEntry path may be used as an ADO.NET connection string.
Name space to be imported when working with Active Directories:
System.DirectoryServices
How do I send an attachment in an email?
The following code shows how to add an attachment to an email.
Using System.IO;
Using System.Web.Mail;
MailAttachment ma=new MailAttachment("c:\sample.txt");
MailMessage mm=new MailMessage();
mm.To ="xyz@programmersheaven.com";
mm.From="abc@yahoo.com";
mm.Body ="Attachment";
mm.Subject="Check out the attached text file";
mm.Attachments.Add(ma);
SmtpMail.SmtpServer="mail.programmersheaven.com";
SmtpMail.Send(mm);
Can I use the Win32 API from a .NET Framework program?
Using platform invoke it's possible. .NET Framework programs can access native code libraries by means of static DLL entry points.
Here is an example of C# calling the Win32 MessageBox function:
using System;
using System.Runtime.InteropServices;
class MainApp
{
[DllImport("user32.dll", EntryPoint="MessageBox")]
public static extern int MessageBox(int hWnd, String
strMessage, String strCaption, uint uiType);
public static void Main()
{
MessageBox(0, "This is PInvoke in operation!",
".NET", 0 );
}
}
What is meant by un-safe code?
Any language capable to read the memory address using pointer which is called as unsafe code.
By un-safe code, it means that the managed program can access the memory address using pointers. There are two points to remember here;
Un-safe code is different from un-managed as it is still managed by the CLR
You still can not perform pointer arithmetic in un-safe code.
What is the difference between Unmanaged and Unsafe code?
Un-managed code runs outside the Common Language Runtime (CLR) control while the unsafe code runs inside the CLR’s control. Both un-safe and un-managed codes may use pointers and direct memory addresses.
What does it mean by VS.NET hot compilation?
The hot compiler highlights the syntax errors in your program as you type the code. The following figure shows an illustration of hot compiler in Visual Studio.NET
What are regions in Visual Studio.NET IDE’s code view?
A region is a part of the code that can be folded/un-folded in the Visual Studio.NET code editor. You can also define your own regions using the #region…#end region block with your code.
What is the difference between the Design View and the Code View of the Visual Studio.NET?
The design view opens the VS.NET form designer that allows you to place user interface controls on the form by simple drag and drop, resize them and set various properties in the convenient way. The designer automatically generates the required code for the program. The code view opens the source code editor that allows you to see the actual code of the program and perform any desired edition.
Different b/w .NET & J2EE ?
Differences between J2EE and the .NET Platform
Vendor Neutrality
The .NET platform is not vendor neutral, it is tied to the Microsoft operating systems. But neither are any of the J2EE implementations
Many companies buy into J2EE believing that it will give them vendor neutrality. And, in fact, this is a stated goal of Sun's vision:
A wide variety of J2EE product configurations and implementations, all of which meet the requirements of this specification, are possible. A portable J2EE application will function correctly when successfully deployed in any of these products. (ref : Java 2 Platform Enterprise Edition Specification, v1.3, page 2-7 available at http://java.sun.com/j2ee/)
Overall Maturity
Given that the .NET platform has a three year lead over J2EE, it should be no surprise to learn that the .NET platform is far more mature than the J2EE platform. Whereas we have high volume highly reliable web sites using .NET technologies (NASDAQ and Dell being among many examples)
Interoperability and Web Services
The .NET platform eCollaboration model is, as I have discussed at length, based on the UDDI and SOAP standards. These standards are widely supported by more than 100 companies. Microsoft, along with IBM and Ariba, are the leaders in this area. Sun is a member of the UDDI consortium and recognizes the importance of the UDDI standards. In a recent press release, Sun's George Paolini, Vice President for the Java Community Development, says:
"Sun has always worked to help establish and support open, standards-based technologies that facilitate the growth of network-based applications, and we see UDDI as an important project to establish a registry framework for business-to-business e-commerce
But while Sun publicly says it believes in the UDDI standards, in reality, Sun has done nothing whatsoever to incorporate any of the UDDI standards into J2EE.
Scalability
Typical Comparision w.r.t Systems and their costs
J2EE
Company System Total Sys. Cost
Bull Escala T610 c/s 16,785 $1,980,179
IBM RS/6000 Enterprise Server F80 16,785 $2,026,681
Bull Escala EPC810 c/s 33,375 $3,037,499
IBM RS/6000 Enterprise Server M80 33,375 $3,097,055
Bull Escala EPC2450 110,403 $9,563,263
IBM IBM eServer pSeries 680 Model 7017-S85 110,403 $9,560,594
.NET platform systems
Company System Total Sys. Cost
Dell PowerEdge 4400 16,263 $273,487
Compaq ProLiant ML-570-6/700-3P 20,207 $201,717
Dell PowerEdge 6400 30,231 $334,626
IBM Netfinity 7600 c/s 32,377 $443,463
Compaq ProLiant 8500-X550-64P 161,720 $3,534,272
Compaq ProLiant 8500-X700-64P 179,658 $3,546,582
Compaq ProLiant 8500-X550-96P 229,914 $5,305,571
Compaq ProLiant 8500-X700-96P 262,244 $5,305,571
Compaq ProLiant 8500-700-192P 505,303 $10,003,826
Framework Support
The .NET platform includes such an eCommerce framework called Commerce Server. At this point, there is no equivalent vendor-neutral framework in the J2EE space. With J2EE, you should assume that you will be building your new eCommerce solution from scratch
Moreover, no matter what [J2EE] vendor you choose, if you expect a component framework that will allow you to quickly field complete e-business applications, you are in for a frustrating experience
Language
In the language arena, the choice is about as simple as it gets. J2EE supports Java, and only Java. It will not support any other language in the foreseeable future. The .NET platform supports every language except Java (although it does support a language that is syntactically and functionally equivalent to Java, C#). In fact, given the importance of the .NET platform as a language independent vehicle, it is likely that any language that comes out in the near future will include support for the .NET platform.
Some companies are under the impression that J2EE supports other languages. Although both IBM's WebSphere and BEA's WebLogic support other languages, neither does it through their J2EE technology. There are only two official ways in the J2EE platform to access other languages, one through the Java Native Interface and the other through CORBA interoperability. Sun recommends the later approach. As Sun's Distinguished Scientist and Java Architect Rick Cattell said in a recent interview.
Portability
The reason that operating system portability is a possibility with J2EE is not so much because of any inherent portability of J2EE, as it is that most of the J2EE vendors support multiple operating systems. Therefore as long as one sticks with a given J2EE vendor and a given database vendor, moving from one operating system to another should be possible. This is probably the single most important benefit in favor of J2EE over the .NET platform, which is limited to the Windows operating system. It is worth noting, however, that Microsoft has submitted the specifications for C# and a subset of the .NET Framework (called the common language infrastructure) to ECMA, the group that standardizes JavaScript.
J2EE offers an acceptable solution to ISVs when the product must be marketed to non-Windows customers, particularly when the J2EE platform itself can be bundled with the ISV's product as an integrated offering.
If the primary customer base for the ISV is Windows customers, then the .NET platform should be chosen. It will provide much better performance at a much lower cost.
Client device independence
The major difference being that with Java, it is the presentation tier programmer that determines the ultimate HTML that will be delivered to the client, and with .NET, it is a Visual Studio.NET control.
This Java approach has three problems. First, it requires a lot of code on the presentation tier, since every possible thin client system requires a different code path. Second, it is very difficult to test the code with every possible thin client system. Third, it is very difficult to add new thin clients to an existing application, since to do so involves searching through, and modifying a tremendous amount of presentation tier logic.
The .NET Framework approach is to write device independent code that interacts with visual controls. It is the control, not the programmer, that is responsible for determining what HTML to deliver, based on the capabilities of the client device.. In the .NET Framework model, one can forget that such a thing as HTML even exists! Contd ....
Conclusion
Sun's J2EE vision is based on a family of specifications that can be implemented by many vendors. It is open in the sense that any company can license and implement the technology, but closed in the sense that it is controlled by a single vendor, and a self contained architectural island with very limited ability to interact outside of itself. One of J2EE's major disadvantages is that the choice of the platform dictates the use of a single programming language, and a programming language that is not well suited for most businesses. One of J2EE's major advantages is that most of the J2EE vendors do offer operating system portability.
Microsoft's .NET platform vision is a family of products rather than specifications, with specifications used primarily to define points of interoperability. The major disadvantage of this approach is that if is limited to the Windows platform, so applications written for the .NET platform can only be run on .NET platforms. Their are several important advantages to the .NET platform:
* The cost of developing applications is much lower, since standard business languages can be used and device independent presentation tier logic can be written.
* The cost of running applications is much lower, since commodity hardware platforms (at 1/5 the cost of their Unix counterparts) can be used.
* The ability to scale up is much greater, with the proved ability to support at least ten times the number of clients any J2EE platform has shown itself able to support.
* Interoperability is much stronger, with industry standard eCollaboration built into the platform.
What are the Main Features of .NET platform?
Features of .NET Platform are :-
Common Language Runtime
Explains the features and benefits of the common language runtime, a run-time environment that manages the execution of code and provides services that simplify the development process.
Assemblies
Defines the concept of assemblies, which are collections of types and resources that form logical units of functionality. Assemblies are the fundamental units of deployment, version control, reuse, activation scoping, and security permissions.
Application Domains
Explains how to use application domains to provide isolation between applications.
Runtime Hosts
Describes the runtime hosts supported by the .NET Framework, including ASP.NET, Internet Explorer, and shell executables.
Common Type System
Identifies the types supported by the common language runtime.
Metadata and Self-Describing Components
Explains how the .NET Framework simplifies component interoperation by allowing compilers to emit additional declarative information, or metadata, into all modules and assemblies.
Cross-Language Interoperability
Explains how managed objects created in different programming languages can interact with one another.
.NET Framework Security
Describes mechanisms for protecting resources and code from unauthorized code and unauthorized users.
.NET Framework Class Library
Introduces the library of types provided by the .NET Framework, which expedites and optimizes the development process and gives you access to system functionality.
What are attributes?
There are at least two types of .NET attribute. The first type I will refer to as a metadata attribute - it allows some data to be attached to a class or method. This data becomes part of the metadata for the class, and (like other class metadata) can be accessed via reflection.
The other type of attribute is a context attribute. Context attributes use a similar syntax to metadata attributes but they are fundamentally different. Context attributes provide an interception mechanism whereby instance activation and method calls can be
pre- and/or post-processed.
What is the use of JIT ?
JIT (Just - In - Time) is a compiler which converts MSIL code to Native Code (ie.. CPU-specific code that runs on the same computer architecture).
Because the common language runtime supplies a JIT compiler for each supported CPU architecture, developers can write a set of MSIL that can be JIT-compiled and run on computers with different architectures. However, your managed code will run only on a specific operating system if it calls platform-specific native APIs, or a platform-specific class library.
JIT compilation takes into account the fact that some code might never get called during execution. 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 needed during execution and stores the resulting native code so that it is accessible for subsequent calls. The loader creates and attaches a stub to each of a type's methods when the type is loaded. On the initial call to the method, the stub passes control to the JIT compiler, which converts the MSIL for that method into native code and modifies the stub to direct execution to the location of the native code. Subsequent calls of the JIT-compiled method proceed directly to the native code that was previously generated, reducing the time it takes to JIT-compile and run the code.
What meant of assembly & global assembly cache (gac) & Meta data.
Assembly :-- An assembly is the primary building block of a .NET based application. It is a collection of functionality that is built, versioned, and deployed as a single implementation unit (as one or more files). All managed types and resources are marked either as accessible only within their implementation unit, or as accessible by code outside that unit. It overcomes the problem of 'dll Hell'.The .NET Framework uses assemblies as the fundamental unit for several purposes:
Security
Type Identity
Reference Scope
Versioning
Deployment
Global Assembly Cache :-- Assemblies can be shared among multiple applications on the machine by registering them in global Assembly cache(GAC). GAC is a machine wide a local cache of assemblies maintained by the .NET Framework. We can register the assembly to global assembly cache by using gacutil command.
We can Navigate to the GAC directory, C:\winnt\Assembly in explore. In the tools menu select the cache properties; in the windows displayed you can set the memory limit in MB used by the GAC
MetaData :-- Assemblies have Manifests. This Manifest contains Metadata information of the Module/Assembly as well as it contains detailed Metadata of other assemblies/modules references (exported). It's the Assembly Manifest which differentiates between an Assembly and a Module.
What are the mobile devices supported by .net platform?
The Microsoft .NET Compact Framework is designed to run on mobile devices such as mobile phones, Personal Digital Assistants (PDAs), and embedded devices. The easiest way to develop and test a Smart Device Application is to use an emulator.
These devices are divided into two main divisions:
1) Those that are directly supported by .NET (Pocket PCs, i-Mode phones, and WAP devices)
2) Those that are not (Palm OS and J2ME-powered devices).
What is GUID , why we use it and where?
GUID :-- GUID is Short form of Globally Unique Identifier, a unique 128-bit number that is produced by the Windows OS or by some Windows applications to identify a particular component, application, file, database entry, and/or user. For instance, a Web site may generate a GUID and assign it to a user's browser to record and track the session. A GUID is also used in a Windows registry to identify COM DLLs. Knowing where to look in the registry and having the correct GUID yields a lot information about a COM object (i.e., information in the type library, its physical location, etc.). Windows also identifies user accounts by a username (computer/domain and username) and assigns it a GUID. Some database administrators even will use GUIDs as primary key values in databases.
GUIDs can be created in a number of ways, but usually they are a combination of a few unique settings based on specific point in time (e.g., an IP address, network MAC address, clock date/time, etc.).
Describe the difference between inline and code behind - which is best in a loosely coupled solution
ASP.NET supports two modes of page development: Page logic code that is written inside runat="server"> blocks within an .aspx file and dynamically compiled the first time the page is requested on the server. Page logic code that is written within an external class that is compiled prior to deployment on a server and linked ""behind"" the .aspx file at run time.
Whats MSIL, and why should my developers need an appreciation of it if at all?
When compiling the source code to managed code, the compiler translates the source into Microsoft intermediate language (MSIL). This is a CPU-independent set of instructions that can efficiently be converted to native code. Microsoft intermediate language (MSIL) is a translation used as the output of a number of compilers. It is the input to a just-in-time (JIT) compiler. The Common Language Runtime includes a JIT compiler for the conversion of MSIL to native code.
Before Microsoft Intermediate Language (MSIL) can be executed it, must be converted by the .NET Framework just-in-time (JIT) compiler to native code. This is CPU-specific code that runs on the same computer architecture as the JIT compiler. Rather than using time and memory to convert all of the MSIL in a portable executable (PE) file to native code. It converts the MSIL as needed whilst executing, then caches the resulting native code so its accessible for any subsequent calls.
What is namespaces?.
Namespace is a logical naming scheme for group related types. Some class types that logically belong together they can be put into a common namespace. They prevent namespace collisions and they provide scoping. They are imported as "using" in C# or "Imports" in Visual Basic. It seems as if these directives specify a particular assembly, but they don't. A namespace can span multiple assemblies, and an assembly can define multiple namespaces. When the compiler needs the definition for a class type, it tracks through each of the different imported namespaces to the type name and searches each referenced assembly until it is found.
Namespaces can be nested. This is very similar to packages in Java as far as scoping is concerned.
What namespaces are necessary to create a localized application?
System.Globalization, System.Resources.
What does this useful command line do? tasklist /m "mscor*"
Lists all the applications and associated tasks/process currently running on the system with a module whose name begins "mscor" loaded into them; which in nearly all cases means "all the .NET processes".
What’s wrong with a line like this? DateTime.Parse(myString);
There is nothing wrong with this declaration. Converts the specified string representation of a date and time to its DateTime equivalent. But If the string is not a valid DateTime, It throws an exception.
What's different about namespace declaration when comparing that to package declaration in Java?
No semicolon.
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