C# Interview Questions and Answers

So let’s say I have an application that uses MyApp.dll assembly, version 1.0.0.0. There is a security bug in that assembly, and I publish the patch, issuing it under name MyApp.dll 1.1.0.0. How do I tell the client applications that are already installed to start using this new MyApp.dll?
Use publisher policy. To configure a publisher policy, use the publisher policy configuration file, which uses a format similar app .config file. But unlike the app .config file, a publisher policy file needs to be compiled into an assembly and placed in the GAC.

What is delay signing?
Delay signing allows you to place a shared assembly in the GAC by signing the assembly with just the public key. This allows the assembly to be signed with the private key at a later stage, when the development process is complete and the component or assembly is ready to be deployed. This process enables developers to work with shared assemblies as if they were strongly named, and it secures the private key of the signature from being accessed at different stages of development.

Is there an equivalent of exit() for quitting a C# .NET application?
Yes, you can use System.Environment.Exit(int exitCode) to exit the application or Application.Exit() if it's a Windows Forms app.

Can you prevent your class from being inherited and becoming a base class for some other classes?
Yes, that is what keyword sealed in the class definition is for. The developer trying to derive from your class will get a message: cannot inherit from Sealed class WhateverBaseClassName. It is the same concept as final class in Java.

Is XML case-sensitive?
Yes, so and are different elements.

If a base class has a bunch of overloaded constructors, and an inherited class has another bunch of overloaded constructors, can you enforce a call from an inherited constructor to an arbitrary base constructor?
Yes, just place a colon, and then keyword base (parameter list to invoke the appropriate constructor) in the overloaded constructor definition inside the inherited class.

I was trying to use an "out int" parameter in one of my functions. How should I declare the variable that I am passing to it?
You should declare the variable as an int, but when you pass it in you must specify it as 'out', like the following:
int i;
foo(out i);
where foo is declared as follows:
[return-type] foo(out int o) { }

How do I make a DLL in C#?
You need to use the /target:library compiler option.

How do I simulate optional parameters to COM calls?
You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.

Will finally block get executed if the exception had not occurred?
Yes.

What is the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception? Does C# support try-catch-finally blocks?
Yes. Try-catch-finally blocks are supported by the C# compiler. Here's an example of a try-catch-finally block: using System;
public class TryTest
{
static void Main()
{
try
{
Console.WriteLine("In Try block");
throw new ArgumentException();
}
catch(ArgumentException n1)
{
Console.WriteLine("Catch Block");
}
finally
{
Console.WriteLine("Finally Block");
}
}
}
Output: In Try Block
Catch Block
Finally Block

If I return out of a try/finally in C#, does the code in the finally-clause run? Yes. The code in the finally always runs. If you return out of the try block, or even if you do a "goto" out of the try, the finally block always runs, as shown in the following
example: using System;
class main
{
public static void Main()
{
try
{
Console.WriteLine("In Try block");
return;
}
finally
{
Console.WriteLine("In Finally block");
}
}
}

Both "In Try block" and "In Finally block" will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it's a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there's an extra store/load of the value of the expression (since it has to be computed within the try block).

Is there regular expression (regex) support available to C# developers?
Yes. The .NET class libraries provide support for regular expressions. Look at the documentation for the System.Text.RegularExpressions namespace.

Is there a way to force garbage collection?
Yes. Set all references to null and then call System.GC.Collect(). If you need to have some objects destructed, and System.GC.Collect() doesn't seem to be doing it for you, you can force finalizers to be run by setting all the references to the object to null and then calling System.GC.RunFinalizers().

Does C# support properties of array types?
Yes. Here's a simple example: using System;
class Class1
{
private string[] MyField;
public string[] MyProperty
{
get { return MyField; }
set { MyField = value; }
}
}
class MainClass
{
public static int Main(string[] args)
{
Class1 c = new Class1();
string[] arr = new string[] {"apple", "banana"};
c.MyProperty = arr;
Console.WriteLine(c.MyProperty[0]); // "apple"
return 0;
}
}

What connections does Microsoft SQL Server support?
Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords)

What is a satellite assembly?
When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.

How is method overriding different from overloading?
When overriding, you change the method behavior for a derived class. Overloading simply involves having a method with the same name within the class.

When do you absolutely have to declare a class as abstract (as opposed to free-willed educated choice or decision based on UML diagram)?
When at least one of the methods in the class is abstract. When the class itself is inherited from an abstract class, but not all base abstract methods have been over-ridden.

Why would you use untrusted verification?
Web Services might use it, as well as non-Windows applications.

What is the implicit name of the parameter that gets passed into the class set method?
Value, and its datatype depends on whatever variable we are changing.

How do I register my code for use by classic COM clients?
Use the regasm.exe utility to generate a type library (if needed) and the necessary entries in the Windows Registry to make a class available to classic COM clients. Once a class is registered in the Windows Registry with regasm.exe, a COM client can use the class as though it were a COM class.

How do I do implement a trace and assert?
Use a conditional attribute on the method, as shown below:
class Debug
{
[conditional("TRACE")]
public void Trace(string s)
{
Console.WriteLine(s);
}
}
class MyClass
{
public static void Main()
{
Debug.Trace("hello");
}
}

In this example, the call to Debug.Trace() is made only if the preprocessor symbol TRACE is defined at the call site. You can define preprocessor symbols on the command line by using the /D switch. The restriction on conditional methods is that they must have void return type.

How do I create a multi language, multi file assembly?
Unfortunately, this is currently not supported in the IDE. To do this from the command line, you must compile your projects into netmodules (/target:module on the C# compiler), and then use the command line tool al.exe (alink) to link these netmodules together.

C# provides a default constructor for me. I write a constructor that takes a string as a parameter, but want to keep the no parameter one. How many constructors should I write?
Two. Once you write at least one constructor, C# cancels the freebie constructor, and now you have to write one yourself, even if there is no implementation in

What is the equivalent to regsvr32 and regsvr32 /u a file in .NET development?
Try using RegAsm.exe. The general syntax would be: RegAsm. A good description of RegAsm and its associated switches is located in the .NET SDK docs. Just search on "Assembly Registration Tool".Explain ACID rule of thumb for transactions.

Transaction must be Atomic (it is one unit of work and does not dependent on previous and following transactions), Consistent (data is either committed or roll back, no in-between case where something has been updated and something hasnot), Isolated (no transaction sees the intermediate results of the current transaction), Durable (the values persist if the data had been committed even if the system crashes right after).

Where is the output of TextWriterTraceListener redirected?
To the Console or a text file depending on the parameter passed to the constructor.

How do I create a multilanguage, single-file assembly?
This is currently not supported by Visual Studio .NET.

Why cannot you specify the accessibility modifier for methods inside the interface?
They all must be public. Therefore, to prevent you from getting the false impression that you have any freedom of choice, you are not allowed to specify any accessibility, it is public by default.

Is it possible to restrict the scope of a field/method of a class to the classes in the same namespace?
There is no way to restrict to a namespace. Namespaces are never units of protection. But if you're using assemblies, you can use the 'internal' access modifier to restrict access to only within the assembly.

Why do I get a syntax error when trying to declare a variable called checked?
The word checked is a keyword in C#.

Why are there five tracing levels in System.Diagnostics.TraceSwitcher?
The tracing dumps can be quite verbose and for some applications that are constantly running you run the risk of overloading the machine and the hard drive there. Five levels range from None to Verbose, allowing to fine-tune the tracing activities.

What is the syntax for calling an overloaded constructor within a constructor (this() and constructorname() does not compile)?
The syntax for calling another constructor is as follows:
class B
{
B(int i)
{ }
}
class C : B
{
C() : base(5) // call base constructor B(5)
{ }
C(int i) : this() // call C()
{ }
public static void Main() {}
}

Why do I get a "CS5001: does not have an entry point defined" error when compiling?
The most common problem is that you used a lowercase 'm' when defining the Main method. The correct way to implement the entry point is as follows:
class test
{
static void Main(string[] args) {}
}

What does the keyword virtual mean in the method definition?
The method can be over-ridden.

What optimizations does the C# compiler perform when you use the /optimize+ compiler option?
The following is a response from a developer on the C# compiler team:
We get rid of unused locals (i.e., locals that are never read, even if assigned).
We get rid of unreachable code.
We get rid of try-catch w/ an empty try.
We get rid of try-finally w/ an empty try (convert to normal code...).
We get rid of try-finally w/ an empty finally (convert to normal code...).
We optimize branches over branches:
gotoif A, lab1
goto lab2:
lab1:
turns into: gotoif !A, lab2
lab1:
We optimize branches to ret, branches to next instruction, and branches to branches.

How can I create a process that is running a supplied native executable (e.g., cmd.exe)?
The following code should run the executable and wait for it to exit before
continuing: using System;
using System.Diagnostics;
public class ProcessTest {
public static void Main(string[] args) {
Process p = Process.Start(args[0]);
p.WaitForExit();
Console.WriteLine(args[0] + " exited.");
}
}
Remember to add a reference to System.Diagnostics.dll when you compile.

What is the difference between the System.Array.CopyTo() and System.Array.Clone()?
The first one performs a deep copy of the array, the second one is shallow.

How do I declare inout arguments in C#?
The equivalent of inout in C# is ref. , as shown in the following
example: public void MyMethod (ref String str1, out String str2)
{
...
}
When calling the method, it would be called like this: String s1;
String s2;
s1 = "Hello";
MyMethod(ref s1, out s2);
Console.WriteLine(s1);
Console.WriteLine(s2);
Notice that you need to specify ref when declaring the function and calling it.

Is there a way of specifying which block or loop to break out of when working with nested loops?
The easiest way is to use goto: using System;
class BreakExample
{
public static void Main(String[] args)
{
for(int i=0; i<3;>{
Console.WriteLine("Pass {0}: ", i);
for( int j=0 ; j<100>{
if ( j == 10) goto done;
Console.WriteLine("{0} ", j);
}
Console.WriteLine("This will not print");
}
done:
Console.WriteLine("Loops complete.");
}
}

What is the difference between const and static read-only?
The difference is that static read-only can be modified by the containing class, but const can never be modified and must be initialized to a compile time constant. To expand on the static read-only case a bit, the containing class can only modify it: -- in the variable declaration (through a variable initializer).
-- in the static constructor (instance constructors if it's not static).

What does the parameter Initial Catalog define inside Connection String?
The database name to connect to.

What is the difference between System.String and System.StringBuilder classes?
System.String is immutable; System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.

What is the top .NET class that everything is derived from?
System.Object.

Can you allow class to be inherited, but prevent the method from being over-ridden?
Yes, just leave the class public and make the method sealed

Can you change the value of a variable while debugging a C# application?
Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.

Are private class-level variables inherited?
Yes, but they are not accessible, so looking at it you can honestly say that they are not inherited. But they are.

Can you inherit multiple interfaces?
Yes. .NET does support multiple interfaces.

From a versioning perspective, what are the drawbacks of extending an interface as opposed to extending a class?
With regard to versioning, interfaces are less flexible than classes. With a class, you can ship version 1 and then, in version 2, decide to add another method. As long as the method is not abstract (i.e., as long as you provide a default implementation of the method), any existing derived classes continue to function with no changes. Because interfaces do not support implementation inheritance, this same pattern does not hold for interfaces. Adding a method to an interface is like adding an abstract method to a base class--any class that implements the interface will break, because the class doesn't implement the new interface method.

Which one is trusted and which one is untrusted?
Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction

What namespaces are necessary to create a localized application?
System.Globalization, System.Resources.

Does Console.WriteLine() stop printing when it reaches a NULL character within a string?
Strings are not null terminated in the runtime, so embedded nulls are allowed. Console.WriteLine() and all similar methods continue until the end of the string.

What is the advantage of using System.Text.StringBuilder over System.String?
StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it is being operated on, a new instance is created.

What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET?
SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but it is a .NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a deprecated layer provided for backward compatibility to ODBC engines.

Why do I get a security exception when I try to run my C# app?
Some security exceptions are thrown if you are working on a network share. There are some parts of the frameworks that will not run if being run off a share (roaming profile, mapped drives, etc.). To see if this is what's happening, just move the executable over to your local drive and see if it runs without the exceptions. One of the common exceptions thrown under these conditions is
System.Security.SecurityException.
To get around this, you can change your security policy for the intranet zone, code group 1.2, (the zone that running off shared folders falls into) by using the caspol.exe tool.

Is there any sample C# code for simple threading?
Some sample code follows: using System;
using System.Threading;
class ThreadTest
{
public void runme()
{
Console.WriteLine("Runme Called");
}
public static void Main(String[] args)
{
ThreadTest b = new ThreadTest();
Thread t = new Thread(new ThreadStart(b.runme));
t.Start();
}
}

What is the difference between // comments, /* */ comments and /// comments?
Single-line, multi-line and XML documentation comments.

What is the difference between and XML documentation tag?
Single line code example and multiple-line code example.

Explain the three services model (three-tier application). Presentation (UI), business (logic and underlying code) and data (from storage or other sources).

What are three test cases you should go through in unit testing? Positive test cases (correct data, correct output), negative test cases (broken or missing data, proper handling), exception test cases (exceptions are thrown and caught properly).

How do you inherit from a class in C#?
Place a colon and then the name of the base class. Notice that it is double colon in C++.

How do I port "synchronized" functions from Visual J++ to C#?
Original Visual J++ code: public synchronized void Run()
{
// function body
}
Ported C# code: class C
{
public void Run()
{
lock(this)
{
// function body
}
}
public static void Main() {}
}

C# interview questions,Asp.net Interview questions, .net material

What's C# ?
C# (pronounced C-sharp) is a new object oriented language from Microsoft and is derived from C and C++. It also borrows a lot of concepts from Java too including garbage collection.

Is it possible to inline assembly or IL in C# code?
- No.

Is it possible to have different access modifiers on the get/set methods of a property?
- No. The access modifier on a property applies to both its get and set accessors. What you need to do if you want them to be different is make the property read-only (by only providing a get accessor) and create a private/internal set method that is separate from the property.

Is it possible to have a static indexer in C#? allowed in C#.
- No. Static indexers are not

If I return out of a try/finally in C#, does the code in the finally-clause run?
-Yes. The code in the finally always runs. If you return out of the try block, or even if you do a goto out of the try, the finally block always runs:
using System;
class main
{
public static void Main()
{
try
{
Console.WriteLine(\"In Try block\");
return;
}
finally
{
Console.WriteLine(\"In Finally block\");
}
}
}

Both In Try block and In Finally block will be displayed. Whether the return is in the try block or after the try-finally block, performance is not affected either way. The compiler treats it as if the return were outside the try block anyway. If it’s a return without an expression (as it is above), the IL emitted is identical whether the return is inside or outside of the try. If the return has an expression, there’s an extra store/load of the value of the expression (since it has to be computed within the try block).

I was trying to use an out int parameter in one of my functions. How should I declare the variable that I am passing to it?

You should declare the variable as an int, but when you pass it in you must specify it as ‘out’, like the following: int i; foo(out i); where foo is declared as follows:
[return-type] foo(out int o) { }

How does one compare strings in C#?
In the past, you had to call .ToString() on the strings when using the == or != operators to compare the strings’ values. That will still work, but the C# compiler now automatically compares the values instead of the references when the == or != operators are used on string types. If you actually do want to compare references, it can be done as follows: if ((object) str1 == (object) str2) { } Here’s an example showing how string compares work:
using System;
public class StringTest
{
public static void Main(string[] args)
{
Object nullObj = null; Object realObj = new StringTest();
int i = 10;
Console.WriteLine(\"Null Object is [\" + nullObj + \"]\n\"
+ \"Real Object is [\" + realObj + \"]\n\"
+ \"i is [\" + i + \"]\n\");
// Show string equality operators
string str1 = \"foo\";
string str2 = \"bar\";
string str3 = \"bar\";
Console.WriteLine(\"{0} == {1} ? {2}\", str1, str2, str1 == str2 );
Console.WriteLine(\"{0} == {1} ? {2}\", str2, str3, str2 == str3 );
}
}

Output:

Null Object is []
Real Object is [StringTest]
i is [10]
foo == bar ? False
bar == bar ? True

How do you specify a custom attribute for the entire assembly (rather than for a class)?
Global attributes must appear after any top-level using clauses and before the first type or namespace declarations. An example of this is as follows:
using System;
[assembly : MyAttributeClass] class X {}
Note that in an IDE-created project, by convention, these attributes are placed in AssemblyInfo.cs.

How do you mark a method obsolete?
[Obsolete] public int Foo() {...}
or
[Obsolete(\"This is a message describing why this method is obsolete\")] public int Foo() {...}
Note: The O in Obsolete is always capitalized.

How do you implement thread synchronization (Object.Wait, Notify,and CriticalSection) in C#?
You want the lock statement, which is the same as Monitor Enter/Exit:
lock(obj) { // code }

translates to

try {
CriticalSection.Enter(obj);
// code
}
finally
{
CriticalSection.Exit(obj);
}

How do you directly call a native function exported from a DLL?
Here’s a quick example of the DllImport attribute in action:

using System.Runtime.InteropServices; \
class C
{
[DllImport(\"user32.dll\")]
public static extern int MessageBoxA(int h, string m, string c, int type);
public static int Main()
{
return MessageBoxA(0, \"Hello World!\", \"Caption\", 0);
}
}

This example shows the minimum requirements for declaring a C# method that is implemented in a native DLL. The method C.MessageBoxA() is declared with the static and external modifiers, and has the DllImport attribute, which tells the compiler that the implementation comes from the user32.dll, using the default name of MessageBoxA. For more information, look at the Platform Invoke tutorial in the documentation.

How do I simulate optional parameters to COM calls?

You must use the Missing class and pass Missing.Value (in System.Reflection) for any values that have optional parameters.

What do you know about .NET assemblies?
Assemblies are the smallest units of versioning and deployment in the .NET application. Assemblies are also the building blocks for programs such as Web services, Windows services, serviced components, and .NET remoting applications.

What’s the difference between private and shared assembly?
Private assembly is used inside an application only and does not have to be identified by a strong name. Shared assembly can be used by multiple applications and has to have a strong name.

What’s a strong name?
A strong name includes the name of the assembly, version number, culture identity, and a public key token.

How can you tell the application to look for assemblies at the locations other than its own install?
Use the directive in the XML .config file for a given application.
< privatepath="c:\mylibs;">
should do the trick. Or you can add additional search paths in the Properties box of the deployed application.

How can you debug failed assembly binds?
Use the Assembly Binding Log Viewer (fuslogvw.exe) to find out the paths searched.

Where are shared assemblies stored?
Global assembly cache.

How can you create a strong name for a .NET assembly?
With the help of Strong Name tool (sn.exe).

Where’s global assembly cache located on the system?
Usually C:\winnt\assembly or C:\windows\assembly.

Can you have two files with the same file name in GAC?
Yes, remember that GAC is a very special folder, and while normally you would not be able to place two files with the same name into a Windows folder, GAC differentiates by version number as well, so it’s possible for MyApp.dll and MyApp.dll to co-exist in GAC if the first one is version 1.0.0.0 and the second one is 1.1.0.0.

SQL Server Stored Procedures

This tutorial gives an overview of how to use SQL Server Stored Procedures in a web application.

Stored Procedures are compiled SQL code stored in the database. Calling stored procedures as opposed to sending over query strings improves the performance of a web application. Not only is there less network traffic since only short commands are sent instead of long query stings, but the execution of the actually code itself also improves. The reason is because a stored procedure is already compiled ahead of time. Stored procedures are also cached by SQL Server when they are run to speed things up for subsequent calls.

Other than performance, stored procedures are also helpful because they provide another layer of abstraction for your web application. For instance, you can change a query in a stored procedure and get different results without having to recompile your objects. Using stored procedures also makes your objects cleaner, and SQL Server’s convenient backup tool makes it easy to back them up.

To create a stored procedure, we can use the SQL Query Analyzer or the SQL Server Enterprise Manager. I find it easier to use the query analyzer because it allows you to test your query before putting it in a procedure and then tests the procedure after it has been created. However, enterprise manager provides an easy interface for viewing all of the existing stored procedures and editing them.

Suppose we have the following query that retrieves messages from a given thread:

SELECT message_id,
       thread_id,
       user_id,
       first_names,
       last_name,
       email,
       subject,
       body,
       date_submitted,
       category_name,
       category_id,
       last_edited
FROM    message_view
WHERE thread_id = @iThreadID
ORDER BY date_submitted asc

To put this query in a stored procedure using the query analyzer, we simply have to give it a name (GetThreadMessages) and tell it what inputs (@iThreadID int) it requires. The name of the procedure goes in the create statement, then come the comma separated inputs, and finally the AS keyword followed by the procedure. The resulting statement would look like this:


Creating the GetThreadMessages procedure using the query analyzer

Then, to test out the procedure in the query analyzer, we just run it with comma separated inputs (there’s only one input in this case).


Executing GetThreadMessages procedure with thread_id 1

Finally, if we want to view it in the enterprise manager, we just go to the stored procedures section, right click on it, and choose properties. Here we can edit it and save our changes. The other options when you right click it allow you to rename it, delete it, and copy it much like you could with a file. Opening up the properties in enterprise manager looks like this.


GetThreadMessages properties under enterprise manager

Now that we’ve made our stored procedure, we just need to execute it from our object model. Executing it from our object model is almost the same as executing a normal query. The only differences are instead of providing the query, we provide the name of the stored procedure, and we also specify that it is a stored procedure. The c# code to do this would look like this (sorry, have to leave out the connection string):

SqlConnection myConnection = new SqlConnection(strConnection);
SqlCommand myCommand  = new SqlCommand("GetThreadMessages", myConnection);
myCommand.CommandType = CommandType.StoredProcedure;

Don’t forget to bind the input variables like you normally would:

SqlParameter ThreadID = new SqlParameter("@iThreadID", SqlDbType.Int, 4);
ThreadID.Value        = iThreadID;
myCommand.Parameters.Add(ThreadID);

Hope you find this somewhat useful.

Voice recording application in asp.net

Do you want to record your voice from Microphone? If yes, you can use the Microsoft APIs to solve this issue. It's a very simple approach to record your voice from Mic. I provided C#.net code to solve this issue.

1. Open C#.net web applications. And added the blow namespace.

using Microsoft.VisualBasic.Devices;
using Microsoft.VisualBasic;
using System.Runtime.InteropServices;

2. Add the below API.
[DllImport("winmm.dll", EntryPoint = "mciSendStringA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
private static extern int mciSendString(string lpstrCommand, string lpstrReturnString, int uReturnLength, int hwndCallback);

3. Create three Buttons and given the below name and text for the buttons.

1. Record
2. SaveStop
3. Read

1. Under Record Button Click paste the below Code:

// record from microphone
mciSendString("open new Type waveaudio Alias recsound", "", 0, 0);
mciSendString("record recsound", "", 0, 0);

2. Under Save / Stop button Click,


// stop and save
mciSendString("save recsound c:\\record.wav", "", 0, 0);
mciSendString("close recsound ", "", 0, 0);
Computer c = new Computer();
c.Audio.Stop();

3. Under Read Button Click

Computer computer = new Computer();
computer.Audio.Play("c:\\record.wav", AudioPlayMode.Background);


Save and Execute it. 

.Net Interview Questions and answers

.NET Architecture

The programming model for the .NET platform.

The .NET Framework provides a managed execution environment, simplified development and deployment, and integration with a wide variety of programming languages.

The .NET Framework has two key parts:

1. The .NET Framework class library is a comprehensive, object-oriented collection of reusable types that you can use to develop applications. The .NET Framework class library includes ADO.NET, ASP.NET and Windows Forms.
2. The common language runtime (CLR) is the core runtime engine for executing applications in the .NET Framework. You can think of the CLR as a safe area - a "sandbox" - inside of which your .NET code runs. Code that runs in the CLR is called managed code.

ADO.NET

The data access component for the .NET Framework.

ADO.NET leverages the power of XML to provide disconnected access to data. ADO.NET is made of a set of classes that are used for connecting to a database, providing access to relational data, XML, application data and retrieving results.

ADO.NET is made of a set of classes that are used for connecting to a database, providing access to relational data, XML, application data, and retrieving results.

ASP.NET

The component of the Microsoft .NET Framework used for building, deploying, and running Web applications and distributed applications.

Assembly

A compiled representation of one or more classes.

Each assembly is self-contained, that is, the assembly includes the metadata about the assembly as a whole.

Assemblies can be private or shared:

* Private assemblies, which are used by a limited number of applications, are placed in the application folder or one of its subfolders. For example, even if the client has two different applications that call a private assembly named formulas, each client application loads the correct assembly.
* Shared assemblies, which are available to multiple client applications, are placed in the Global Assembly Cache (GAC). Each shared assembly is assigned a strong name to handle name and version conflicts.

Assembly Cache

A code cache used for side-by-side storage of assemblies.

The assembly cache is made of two parts:

* The global assembly cache contains assemblies that are explicitly installed to be shared among many applications on the computer.
* The download cache is a directory inside the assembly cache that stores code downloaded from the Internet or intranet site and isolated to the application that caused the download. This isolation prevents code downloaded on behalf of one application from affecting other applications.

Code Access Security (CAS)

The component of the Microsoft .NET Framework used for building, deploying and running Web applications and distributed applications.

Common Language Runtime (CLR)

The core runtime engine in the Microsoft .NET Framework. The CLR supplies services such as cross-language integration, code access security, object lifetime management and debugging support. Applications that run in the CLR are sometimes said to be running "in the sandbox."

Download Cache

The subdirectory in assembly cache that stores code downloaded from Internet or intranet sites, isolated to the application that caused the download. This isolation prevents code downloaded on behalf of one application from affecting other applications.

DTC (Distributed Transaction Coordinator)

In Microsoft Windows NT, Windows 2000, Windows XP and the Windows Server 2003 family, the DTC is a system service that is part of COM+ services.

COM+ components that use DTC can enlist .NET connections in distributed transactions. This makes it possible to scale transactions from one to many computers without adding special code.

Expose

To host and make available a Web service so that it can be used by other applications or services.

Garbage Collection

A process in the CLR that automatically frees allocated objects when there are no longer any outstanding references to them. The developer does not need to explicitly free memory assigned to an object.

Global Assembly Cache (GAC)

The part of the assembly cache that stores assemblies specifically installed to be shared by many applications on the computer. Applications deployed in the global assembly cache must have a strong name to handle name and version conflicts.

Isolation Level

An isolation level represents a particular locking strategy employed in the database system to improve data consistency. The higher the isolation level, the more complex the locking strategy behind it.

The isolation level provided by the database determines whether a transaction will encounter defined behaviors in data consistency.

The American National Standards Institute (ANSI) defines four isolation levels:

1. Read uncommitted (0)
2. Read committed (1)
3. Repeatable read (2)
4. Serializable (3)

JIT Compiler

The "just-in-time" compilation that converts Microsoft intermediate language (MSIL) into machine code at the point when the code is required at run time.

Locking Level

Locking is a database operation that restricts a user from accessing a table or record. Locking is used in situations when more than one user might try to use the same table at the same time. By locking the table or record, only one user at a time can affect the data.

Managed Code

Code executed and managed by the .NET Framework, specifically by the CLR. Managed code must supply the information necessary for the CLR to provide services such as memory management and code access security.

Microsoft .NET Framework

The Microsoft .NET Framework has two key parts:

1. The .NET Framework class library is a comprehensive, object-oriented collection of reusable types that you can use to develop applications. The .NET Framework class library includes ADO.NET, ASP.NET and Windows Forms.
2. The common language runtime (CLR) is the core runtime engine for executing applications in the .NET Framework. You can think of the CLR as a safe area - a "sandbox" - inside of which your .NET code runs. Code that runs in the CLR is called managed code.

Microsoft Intermediate Language (MSIL)

A CPU-independent set of instructions that can be 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.

Namespace

A logical naming scheme for grouping related types.

The .NET Framework uses a hierarchical naming scheme for grouping types into logical categories of related functionality, such as the ASP.NET technology or remoting functionality. Design tools can use namespaces to make it easier for developers to browse and reference types in their code.

A single assembly can contain types whose hierarchical names have different namespace roots, and a logical namespace root can span multiple assemblies.

In the .NET Framework, a namespace is a logical design-time naming convenience, whereas an assembly establishes the name scope for types at run time.

No-touch Deployment

A feature of the .NET Framework, similar to browser-based application deployment, that lets clients download the assemblies they need from a remote web server.

The first time an assembly is referenced, it is downloaded to the download cache on the client and executed. After that, when the client accesses the application, the application checks the server to find out whether any assemblies have been updated. Any new assemblies are downloaded to the download cache on the client, refreshing the application without any interaction with the end user.

Side-by-side Execution

The ability to install and use multiple versions of the same assembly in isolation at the same time. Allowing different versions of assemblies to coexist and to execute simultaneously on the same computer enables robust versioning.

Simple Object Access Protocol (SOAP)

A simple, XML-based protocol for exchanging structured data and type information over the Internet. SOAP is currently the de facto standard for XML messaging.

SOAP consists of:

* An envelope that defines a framework for describing message structure.
* A set of encoding rules for expressing instances of application-defined data types.
* A convention for using SOAP with HTTP.

Strong Name

A name that consists of an assembly's text name, version number and culture information (if provided), with a public key and a digital signature generated over the assembly.

Assemblies with the same strong name should be identical. Strong names provide a strong integrity check, because the .NET Framework security checks to be sure that the contents of the assembly have not been changed since it was built.

Universal Description, Discover, and Integration (UDDI)

A platform-independent framework that provides a way to locate and register Web services on the Internet.

The UDDI specification calls for three elements, similar to a telephone book:

1. White pages; which provide business contact information
2. Yellow pages; which organize Web services into categories (for example, credit card authorization services)
3. Green pages; which provide detailed technical information about individual services.

The UDDI specification also contains an operational registry.

Unicode

A standard that software can use to support multi-lingual character sets.

The .NET Framework uses UTF-16 Unicode encoding to represent characters. .NET applications use encoding and decoding to map character representations between Unicode and non-Unicode formats. The .NET Framework also provides UTF-8, ASCII, and ANSI/ISO encodings.

Unmanaged Code

Code that is executed directly by the operating system, outside of the CLR.

Unmanaged code includes all code written before the .NET Framework was introduced. This includes code written to use COM, native Win32 and Visual Basic 6. Because it does not run inside the .NET environment, unmanaged code cannot make use of any .NET managed facilities.

Web Forms

An ASP.NET feature that can be used to create the user interface for Web applications.

The Web Forms page works as a container for the static text and controls you want to display. The programming logic for the Web Forms page resides in a separate file from the user interface file. This file is referred to as the "code-behind" file and has an ".aspx.vb" or ".aspx.cs" extension, depending on whether the code-behind file was written in Visual Basic or Visual C#.

Web Services

A set of modular applications or "services" that can be accessed within a network (e.g., the Internet, an intranet, or extranet) through a standard interface, typically XML.