.NET developers often uses Visual Studio IDE. This tool is great which allow you to build, debug, test and deploy .NET applications. There are many open source free tools which can be used during the development process, some of them are
SharpDevelop: This is an open source IDE, which allows you to build .NET applications. You can download the source, or a friendly setup program.
CSharp Express: This is a free .NET IDE from Microsoft.
Reflector: A very feature rich object browser, decompiler, source code generation tool. Must have!
Kaxaml: If you are interested in WPF development, you will want this free tool, which allows you to enter in any valid XAML markup, and see the results real time. Very helpful way to learn the grammar of XAML, without the overhead of a Visual Studio WPF project.
LinqPad: If you are interested in LINQ, this graphical tool allows you to enter LINQ queries and view the results.
Regards,
Mitesh Mehta
miteshvmeha@gmail.com
Wednesday, October 27, 2010
Monday, September 27, 2010
MVP (model View Presenter) Pattern
Model basically concentrate data only. And again which is going to be filled by presenter. Model is present inside the View.
Provider is the one which is used to get Data from the Web Services in Asp.Net and fills the Model and give that to Presenter and then presenter provide back that to UI.
A very good explanation is at :
http://weblogs.asp.net/scottcate/archive/2007/04/12/very-quick-mvp-pattern-to-use-with-asp-net.aspx
Regards,
Mitesh Mehta
miteshvmehta@gmail.com
Provider is the one which is used to get Data from the Web Services in Asp.Net and fills the Model and give that to Presenter and then presenter provide back that to UI.
A very good explanation is at :
http://weblogs.asp.net/scottcate/archive/2007/04/12/very-quick-mvp-pattern-to-use-with-asp-net.aspx
Regards,
Mitesh Mehta
miteshvmehta@gmail.com
Friday, March 14, 2008
What are the different types of caching?
Caching is a technique widely used in computing to increase performance by keeping frequently accessed or expensive data in memory. In context of web application, caching is used to retain the pages or data across HTTP requests and reuse them without the expense of recreating them.ASP.NET has 3 kinds of caching strategiesOutput CachingFragment CachingData
CachingOutput Caching: Caches the dynamic output generated by a request. Some times it is useful to cache the output of a website even for a minute, which will result in a better performance. For caching the whole page the page should have OutputCache directive.<%@ OutputCache Duration="60" VaryByParam="state" %>
Fragment Caching: Caches the portion of the page generated by the request. Some times it is not practical to cache the entire page, in such cases we can cache a portion of page<%@ OutputCache Duration="120" VaryByParam="CategoryID;SelectedID"%>
Data Caching: Caches the objects programmatically. For data caching asp.net provides a cache object for eg: cache["States"] = dsStates;
What are user controls and custom controls?
Custom controls:
A control authored by a user or a third-party software vendor that does not belong to the .NET Framework class library. This is a generic term that includes user controls.
A control authored by a user or a third-party software vendor that does not belong to the .NET Framework class library. This is a generic term that includes user controls.
A custom server control is used in Web Forms (ASP.NET pages). A custom client control is used in Windows Forms applications.
User Controls:
In ASP.NET: A user-authored server control that enables an ASP.NET page to be re-used as a server control. An ASP.NET user control is authored declaratively and persisted as a text file with an .ascx extension. The ASP.NET page framework compiles a user control on the fly to a class that derives from the System.Web.UI.UserControl class.
What is view state and use of it?
The current property settings of an ASP.NET page and those of any ASP.NET server controls contained within the page. ASP.NET can detect when a form is requested for the first time versus when the form is posted (sent to the server), which allows you to program accordingly.
What method do you use to explicitly kill a users session in ASP.NET?
The Session.Abandon method destroys all the objects stored in a Session object and releases their resources. If you do not call the Abandon method explicitly, the server destroys these objects when the session times out.
What is smart navigation in ASP.NET Pages?
When a page is requested by an Internet Explorer 5 browser, or later, smart navigation enhances the user's experience of the page by performing the following:
- Eliminating the flash caused by navigation.
- Persisting the scroll position when moving from page to page.
- Persisting element focus between navigations.
- Retaining only the last page state in the browser's history.
- Smart navigation is best used with ASP.NET pages that require frequent postbacks but with visual content that does not change dramatically on return. Consider this carefully when deciding whether to set this property to true.
Response.Redirect vs Server.Transfer?
Server.Transfer or Response.Redirect both are the method of choice for transferring the user from one place in the application to another
Server.Transfer is similar in that it sends the user to another page with a statement such as Server.Transfer("WebForm2.aspx"). However, the statement has a number of distinct advantages and disadvantages.
Firstly, transferring to another page using Server.Transfer conserves server resources. Instead of telling the browser to redirect, it simply changes the "focus" on the Web server and transfers the request. This means you don't get quite as many HTTP requests coming through, which therefore eases the pressure on your Web server and makes your applications run faster. But watch out: because the "transfer" process can work on only those sites running on the server, you can't use Server.Transfer to send the user to an external site. Only Response.Redirect can do that.
The other side debates that Server.Transfer is not user friendly because the page requested may not be the page that shows in the URL. Response.Redirect is more user-friendly, as the site visitor can bookmark the page that they are redirected to.
Secondly, Server.Transfer maintains the original URL in the browser. This can really help streamline data entry techniques, although it may make for confusion when debugging.
That's not all: The Server.Transfer method also has a second parameter"preserveForm". If you set this to True, using a statement such as Server.Transfer("WebForm2.aspx", True), the existing query string and any form variables will still be available to the page you are transferring to.
For example, if your WebForm1.aspx has a TextBox control called TextBox1 and you transferred to WebForm2.aspx with the preserveForm parameter set to True, you'd be able to retrieve the value of the original page TextBox control by referencing Request.Form("TextBox1").
Server.Transfer is similar in that it sends the user to another page with a statement such as Server.Transfer("WebForm2.aspx"). However, the statement has a number of distinct advantages and disadvantages.
Firstly, transferring to another page using Server.Transfer conserves server resources. Instead of telling the browser to redirect, it simply changes the "focus" on the Web server and transfers the request. This means you don't get quite as many HTTP requests coming through, which therefore eases the pressure on your Web server and makes your applications run faster. But watch out: because the "transfer" process can work on only those sites running on the server, you can't use Server.Transfer to send the user to an external site. Only Response.Redirect can do that.
The other side debates that Server.Transfer is not user friendly because the page requested may not be the page that shows in the URL. Response.Redirect is more user-friendly, as the site visitor can bookmark the page that they are redirected to.
Secondly, Server.Transfer maintains the original URL in the browser. This can really help streamline data entry techniques, although it may make for confusion when debugging.
That's not all: The Server.Transfer method also has a second parameter"preserveForm". If you set this to True, using a statement such as Server.Transfer("WebForm2.aspx", True), the existing query string and any form variables will still be available to the page you are transferring to.
For example, if your WebForm1.aspx has a TextBox control called TextBox1 and you transferred to WebForm2.aspx with the preserveForm parameter set to True, you'd be able to retrieve the value of the original page TextBox control by referencing Request.Form("TextBox1").
Explain the concept of Web Application.?
An introduction to web applications
A web application consists of a set of web pages that are generated in response to user requests. The Internet has many different types of web applications, such as search engines, online stores, auctions, news sites, discussion groups, games, and so on.
Properties of web applications
A web application consists of a set of web pages that are generated in response to user requests. The Internet has many different types of web applications, such as search engines, online stores, auctions, news sites, discussion groups, games, and so on.
Properties of web applications
- Web applications are a type of client/server application. In that type of application, a user at a client computer accesses an application at a server computer. In a web application, the client and server computers are connected via the Internet or via an intranet (a local area network).
- In a web application, the user works with a web browser at the client computer. The web browser provides the user interface for the application. The most popular web browsers are Microsofts Internet Explorer, .Mozilla Firefox
- The application runs on the server computer under the control of web server software. For ASP.NET web applications, the server must run Microsofts web server, called Internet Information Services, or IIS.
- For most web applications, the server computer also runs a database management system, or DBMS, such as Microsofts SQL Server. The DBMS provides access to information stored in a database. To improve performance on larger applications, the DBMS can be run on a separate server computer.
- The user interface for a web application is implemented as a series of web pages that are displayed in the web browser. Each web page is defined by a web form using HTML, or Hypertext Markup Language, which is a standardized set of markup tags.
- The web browser and web server exchange information using HTTP (Hypertext Transfer Protocol).
What is ASP.NET?
ASP.NET is a technology for creating dynamic Web applications. It is part of the .NET Framework; you can write ASP.NET applications in most .NET compatible languages, including Visual Basic, C#, J# and JScript. ASP.NET pages (Web Forms) are compiled, providing better performance than with scripting languages.
Web Forms allow you to build powerful forms-based Web pages. When building these pages, you can use ASP.NET server controls to create common UI elements, and program them for common tasks. These controls allow you to rapidly build a Web Form out of reusable built-in or custom components, simplifying the code of a page.ASP.NET provides a programming model, and infrastructure, to make creating scalable, secure and stable applications faster, and easier than with previous Web technologies
Tuesday, February 06, 2007
Creational Patterns – Singleton
Introduction
Most programming involves usage of Design Patterns in one form or other .There are around 23 Design Patterns that are available. They are categorized as given below:
I] Creational Patterns
1. Singleton
2. Factory
3. Abstract Factory
4. Builder
5. Prototype
II] Structural Patterns
1. Adapter
2. Bridge
3. Composite
4. Decorator
5. Facade
6. Flyweight
7. Proxy
III] Behavioral Pattern
1. Chain Of Responsibility
2. Command
3. Interpreter
4. Iterator
5. Mediator
6. Memento
7. Observer
8. State
9. Strategy
10. Template Method
11. Visitor
This paper discusses the implementation of the Singleton Design Pattern.
The Concept
Design patterns are commonly defined as time-tested solutions to recurring design problems.
The most striking benefits of Design Patterns are as follows:
They provide you with a way to solve issues related to software development using a proven solution. The solution facilitates the development of highly cohesive modules with minimal coupling. They isolate the variability that may exist in the system requirements, making the overall system easier to understand and maintain.
Design patterns make communication between designers more efficient. Software professionals can immediately picture the high-level design in their thoughts immediately the name of the pattern used to solve a particular issue when discussing system design
Singleton Pattern: In the Singleton Pattern we have at any given instance a single instance of the Singleton Class active. All instantiation of the Singleton Class references the same instance of the Class. The pattern also provides a global point of access to the sole instance of the class.
Class Diagram
Sequence Diagram
Implementation
Steps for implementing the Singleton Pattern:
Step1:
Create a project of type Console Application. Name it SingletonTest.
Step2:
Add a Class File named Singleton and add the following code
///
/// Summary description for Singleton.
///
public class Singleton
{
//Fields
private static Singleton instance;
///
/// Standard default Constructor
///
protected Singleton() {}
///
/// Static method for creating the single instance
/// of the Constructor
///
///
public static Singleton Instance()
{
// initialize if not already done
if( instance == null )
instance = new Singleton();
// return the initialized instance of the Singleton Class
return instance;
}
}
Step 3:
Create a Client class that would access the Singleton Class as follows :
///
/// Summary description for Client.
///
class Client
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main(string[] args)
{
// Constructor is protected -- cannot use new
Singleton s1 = Singleton.Instance();
Singleton s2 = Singleton.Instance();
if( s1 == s2 )
Console.WriteLine( "The same instance" );
Console.ReadLine();
}
}
Step 4:
Run the Application it would display the following output:
Refer Output image
Conclusion
Thus we have implemented the Singleton Design Pattern using the .Net framework.Like any Concepts/Theory Singleton Pattern also has its pros and cons.
Benefits of Singleton Pattern:
1. Instance control: Singleton prevents other objects from instantiating their own copies of the Singleton object, ensuring that all objects access the single instance.
2. Flexibility: Because the class controls the instantiation process, the class has the flexibility to change the instantiation process.
Drawbacks of Singleton Pattern:
1. Overhead. Although the amount is minuscule, there is some overhead involved in checking whether an instance of the class already exists every time an object requests a reference. This problem can be overcome by using static initialization
2. Possible development confusion. When using a singleton object (especially one defined in a class library), developers must remember that they cannot use the new keyword to instantiate the object. Because application developers may not have access to the library source code, they may be surprised to find that they cannot instantiate this class directly.
3. Object lifetime. Singleton does not address the issue of deleting the single object. In languages that provide memory management (for example, languages based on the .NET Framework), only the Singleton class could cause the instance to be deallocated because it holds a private reference to the instance. In languages, such as C++, other classes could delete the object instance, but doing so would lead to a dangling reference inside the Singleton class.
Most programming involves usage of Design Patterns in one form or other .There are around 23 Design Patterns that are available. They are categorized as given below:
I] Creational Patterns
1. Singleton
2. Factory
3. Abstract Factory
4. Builder
5. Prototype
II] Structural Patterns
1. Adapter
2. Bridge
3. Composite
4. Decorator
5. Facade
6. Flyweight
7. Proxy
III] Behavioral Pattern
1. Chain Of Responsibility
2. Command
3. Interpreter
4. Iterator
5. Mediator
6. Memento
7. Observer
8. State
9. Strategy
10. Template Method
11. Visitor
This paper discusses the implementation of the Singleton Design Pattern.
The Concept
Design patterns are commonly defined as time-tested solutions to recurring design problems.
The most striking benefits of Design Patterns are as follows:
They provide you with a way to solve issues related to software development using a proven solution. The solution facilitates the development of highly cohesive modules with minimal coupling. They isolate the variability that may exist in the system requirements, making the overall system easier to understand and maintain.
Design patterns make communication between designers more efficient. Software professionals can immediately picture the high-level design in their thoughts immediately the name of the pattern used to solve a particular issue when discussing system design
Singleton Pattern: In the Singleton Pattern we have at any given instance a single instance of the Singleton Class active. All instantiation of the Singleton Class references the same instance of the Class. The pattern also provides a global point of access to the sole instance of the class.
Class Diagram
Sequence Diagram
Implementation
Steps for implementing the Singleton Pattern:
Step1:
Create a project of type Console Application. Name it SingletonTest.
Step2:
Add a Class File named Singleton and add the following code
///
/// Summary description for Singleton.
///
public class Singleton
{
//Fields
private static Singleton instance;
///
/// Standard default Constructor
///
protected Singleton() {}
///
/// Static method for creating the single instance
/// of the Constructor
///
///
public static Singleton Instance()
{
// initialize if not already done
if( instance == null )
instance = new Singleton();
// return the initialized instance of the Singleton Class
return instance;
}
}
Step 3:
Create a Client class that would access the Singleton Class as follows :
///
/// Summary description for Client.
///
class Client
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main(string[] args)
{
// Constructor is protected -- cannot use new
Singleton s1 = Singleton.Instance();
Singleton s2 = Singleton.Instance();
if( s1 == s2 )
Console.WriteLine( "The same instance" );
Console.ReadLine();
}
}
Step 4:
Run the Application it would display the following output:
Refer Output image
Conclusion
Thus we have implemented the Singleton Design Pattern using the .Net framework.Like any Concepts/Theory Singleton Pattern also has its pros and cons.
Benefits of Singleton Pattern:
1. Instance control: Singleton prevents other objects from instantiating their own copies of the Singleton object, ensuring that all objects access the single instance.
2. Flexibility: Because the class controls the instantiation process, the class has the flexibility to change the instantiation process.
Drawbacks of Singleton Pattern:
1. Overhead. Although the amount is minuscule, there is some overhead involved in checking whether an instance of the class already exists every time an object requests a reference. This problem can be overcome by using static initialization
2. Possible development confusion. When using a singleton object (especially one defined in a class library), developers must remember that they cannot use the new keyword to instantiate the object. Because application developers may not have access to the library source code, they may be surprised to find that they cannot instantiate this class directly.
3. Object lifetime. Singleton does not address the issue of deleting the single object. In languages that provide memory management (for example, languages based on the .NET Framework), only the Singleton class could cause the instance to be deallocated because it holds a private reference to the instance. In languages, such as C++, other classes could delete the object instance, but doing so would lead to a dangling reference inside the Singleton class.
Tuesday, October 31, 2006
Singleton Design Pattern
The Concept Design patterns are commonly defined as time-tested solutions to recurring design problems.
The most striking benefits of Design Patterns are as follows:
They provide you with a way to solve issues related to software development using a proven solution. The solution facilitates the development of highly cohesive modules with minimal coupling. They isolate the variability that may exist in the system requirements, making the overall system easier to understand and maintain.
Design patterns make communication between designers more efficient. Software professionals can immediately picture the high-level design in their thoughts immediately the name of the pattern used to solve a particular issue when discussing system design
Singleton Pattern: In the Singleton Pattern we have at any given instance a single instance of the Singleton Class active. All instantiation of the Singleton Class references the same instance of the Class. The pattern also provides a global point of access to the sole instance of the class.
Class Diagram
Sequence Diagram
Implementation
Steps for implementing the Singleton Pattern:
Step1: Create a project of type Console Application. Name it SingletonTest.
Step2:Add a Class File named Singleton and add the following code
///
/// Summary description for Singleton.
///
public class Singleton
{
//Fields
private static Singleton instance;
///
/// Standard default Constructor
///
protected Singleton() {}
///
/// Static method for creating the single instance
/// of the Constructor
///
///
public static Singleton Instance()
{
// initialize if not already done
if( instance == null )
instance = new Singleton();
// return the initialized instance of the Singleton Class
return instance;
}
}
Step 3:Create a Client class that would access the Singleton Class as follows :
///
/// Summary description for Client.
///
class Client
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main(string[] args)
{
// Constructor is protected -- cannot use newSingleton s1 = Singleton.Instance();Singleton s2 = Singleton.Instance();if( s1 == s2 )Console.WriteLine( "The same instance" );Console.ReadLine();}}
Step 4:Run the Application it would display the following output:
ConclusionThus we have implemented the Singleton Design Pattern using the .Net framework.Like any Concepts/Theory Singleton Pattern also has its pros and cons. Benefits of Singleton Pattern:1. Instance control: Singleton prevents other objects from instantiating their own copies of the Singleton object, ensuring that all objects access the single instance.2. Flexibility: Because the class controls the instantiation process, the class has the flexibility to change the instantiation process.Drawbacks of Singleton Pattern:1. Overhead. Although the amount is minuscule, there is some overhead involved in checking whether an instance of the class already exists every time an object requests a reference. This problem can be overcome by using static initialization2. Possible development confusion. When using a singleton object (especially one defined in a class library), developers must remember that they cannot use the new keyword to instantiate the object. Because application developers may not have access to the library source code, they may be surprised to find that they cannot instantiate this class directly.3. Object lifetime. Singleton does not address the issue of deleting the single object. In languages that provide memory management (for example, languages based on the .NET Framework), only the Singleton class could cause the instance to be deallocated because it holds a private reference to the instance. In languages, such as C++, other classes could delete the object instance, but doing so would lead to a dangling reference inside the Singleton class.
The most striking benefits of Design Patterns are as follows:
They provide you with a way to solve issues related to software development using a proven solution. The solution facilitates the development of highly cohesive modules with minimal coupling. They isolate the variability that may exist in the system requirements, making the overall system easier to understand and maintain.
Design patterns make communication between designers more efficient. Software professionals can immediately picture the high-level design in their thoughts immediately the name of the pattern used to solve a particular issue when discussing system design
Singleton Pattern: In the Singleton Pattern we have at any given instance a single instance of the Singleton Class active. All instantiation of the Singleton Class references the same instance of the Class. The pattern also provides a global point of access to the sole instance of the class.
Class Diagram
Sequence Diagram
Implementation
Steps for implementing the Singleton Pattern:
Step1: Create a project of type Console Application. Name it SingletonTest.
Step2:Add a Class File named Singleton and add the following code
///
/// Summary description for Singleton.
///
public class Singleton
{
//Fields
private static Singleton instance;
///
/// Standard default Constructor
///
protected Singleton() {}
///
/// Static method for creating the single instance
/// of the Constructor
///
///
public static Singleton Instance()
{
// initialize if not already done
if( instance == null )
instance = new Singleton();
// return the initialized instance of the Singleton Class
return instance;
}
}
Step 3:Create a Client class that would access the Singleton Class as follows :
///
/// Summary description for Client.
///
class Client
{
///
/// The main entry point for the application.
///
[STAThread]
static void Main(string[] args)
{
// Constructor is protected -- cannot use newSingleton s1 = Singleton.Instance();Singleton s2 = Singleton.Instance();if( s1 == s2 )Console.WriteLine( "The same instance" );Console.ReadLine();}}
Step 4:Run the Application it would display the following output:
ConclusionThus we have implemented the Singleton Design Pattern using the .Net framework.Like any Concepts/Theory Singleton Pattern also has its pros and cons. Benefits of Singleton Pattern:1. Instance control: Singleton prevents other objects from instantiating their own copies of the Singleton object, ensuring that all objects access the single instance.2. Flexibility: Because the class controls the instantiation process, the class has the flexibility to change the instantiation process.Drawbacks of Singleton Pattern:1. Overhead. Although the amount is minuscule, there is some overhead involved in checking whether an instance of the class already exists every time an object requests a reference. This problem can be overcome by using static initialization2. Possible development confusion. When using a singleton object (especially one defined in a class library), developers must remember that they cannot use the new keyword to instantiate the object. Because application developers may not have access to the library source code, they may be surprised to find that they cannot instantiate this class directly.3. Object lifetime. Singleton does not address the issue of deleting the single object. In languages that provide memory management (for example, languages based on the .NET Framework), only the Singleton class could cause the instance to be deallocated because it holds a private reference to the instance. In languages, such as C++, other classes could delete the object instance, but doing so would lead to a dangling reference inside the Singleton class.
Monday, April 18, 2005
What is so sharp about C#?
I was going through a list of articles available on the INETA website. I came across an article with the heading “Why C # is sharp and why is VB.NET basic?” Hmmm… However, the author has no intentions of looking down upon VB. I have done quite a few projects in VB 6. I am still a VB enthusiast because what I like most about it, is its simplicity and ability to do amazing stuff with little effort (directly proportional to coding?? Ahem…).
A few days back, I had read an extensive comparison between 11 languages in the September 2004 edition of DIQ (Developer IQ http://www.developeriq.com). It was called “The Great Language Shootout”. The article tabulates the results with C# scoring an overall 68pts and Java landing at 65pts. The article also explains in detail about the evaluation process. These figures are clearly just indicators of a test process and cannot form the basis to decide the power and application of any language or its future.
Unable to resist the temptation, I decided to write a simple HelloWorld… nope not just World… HelloManagedWorld program in C#. Managed because, I’m using the .NET csc compiler.
The code:
using System;
class helloManagedWorld
{
static void Main()
{
Console.WriteLine("Hello Managed World!");
}
}
Some explanation:
The using System; directive references a namespace called System that is provided by the Microsoft .NET Framework class library. This namespace contains the Console class referred to in the Main method. Namespaces provide a hierarchical means of organizing the elements of one or more programs. A “using” directive enables unqualified use of the types that are members of the namespace. The “Hello Managed World!” program uses Console.WriteLine as shorthand for System.Console.WriteLine.
The Main method is a member of the class helloManagedWorld. It has the static modifier, and so it is a method on the class helloManagedWorld rather than on instances of this class.
The entry point for an application—the method that is called to begin execution—is always a static method named Main.
How to compile the geeky way (ie. if you only have the .NET Framework, without VS.NET):
I started off with some errors as usual... case sensitivity and some syntax problems…
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
helloWorld.cs(4,30): error CS1552: Array type specifier, [], must appear before
parameter name
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
error CS5001: Program 'helloWorld.exe' does not have an entry point defined
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>helloWorld
Hello World!
Wasn’t that simple enough? So this is just the beginning. Lets see where I go from here. :-)
A few days back, I had read an extensive comparison between 11 languages in the September 2004 edition of DIQ (Developer IQ http://www.developeriq.com). It was called “The Great Language Shootout”. The article tabulates the results with C# scoring an overall 68pts and Java landing at 65pts. The article also explains in detail about the evaluation process. These figures are clearly just indicators of a test process and cannot form the basis to decide the power and application of any language or its future.
Unable to resist the temptation, I decided to write a simple HelloWorld… nope not just World… HelloManagedWorld program in C#. Managed because, I’m using the .NET csc compiler.
The code:
using System;
class helloManagedWorld
{
static void Main()
{
Console.WriteLine("Hello Managed World!");
}
}
Some explanation:
The using System; directive references a namespace called System that is provided by the Microsoft .NET Framework class library. This namespace contains the Console class referred to in the Main method. Namespaces provide a hierarchical means of organizing the elements of one or more programs. A “using” directive enables unqualified use of the types that are members of the namespace. The “Hello Managed World!” program uses Console.WriteLine as shorthand for System.Console.WriteLine.
The Main method is a member of the class helloManagedWorld. It has the static modifier, and so it is a method on the class helloManagedWorld rather than on instances of this class.
The entry point for an application—the method that is called to begin execution—is always a static method named Main.
How to compile the geeky way (ie. if you only have the .NET Framework, without VS.NET):
I started off with some errors as usual... case sensitivity and some syntax problems…
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
helloWorld.cs(4,30): error CS1552: Array type specifier, [], must appear before
parameter name
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
error CS5001: Program 'helloWorld.exe' does not have an entry point defined
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc helloWorld.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>helloWorld
Hello World!
Wasn’t that simple enough? So this is just the beginning. Lets see where I go from here. :-)
Types in C#
First time I saw the C# code in a magazine, I thought, Another new language, new syntax, new keywords…more confusion”. But now I don’t think so. C# is not completely different from other languages speaking of its syntax and approach. Moving further on, I learnt about the data types in C#.
C# supports two kinds of types: value types and reference types. No big deal. The name says it all. In case of values types, the variable stores the value directly and in case of reference types, it stores the reference to the variable (address). Other concepts like possibility of two variables referencing the same object are possible as in the case of C++.
A sample program to understand the types:
using System;
class ClassObj
{
public int num = 0;
}
class ClassTest
{
static void Main()
{
int x = 0;
int y = x;
y = 101;
ClassObj ref1 = new ClassObj();
ClassObj ref2 = ref1;
ref2.num = 999;
Console.WriteLine("Values: {0}, {1}", x, y);
Console.WriteLine("Refs: {0}, {1}", ref1.num, ref2.num);
}
}
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc D:\cstypes.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>cstypes
Values: 0, 101
Refs: 999, 999
An interesting thing that I’ve observed is the method used to print the formatted output in Console.WriteLine
Console.WriteLine takes a variable number of arguments. The first argument is a string, which may contain numbered placeholders like {0} and {1}. Each placeholder refers to a trailing argument with {0} referring to the second argument, {1} referring to the third argument, and so on. Before the output is sent to the console, each placeholder is replaced with the formatted value of its corresponding argument.
C# supports two kinds of types: value types and reference types. No big deal. The name says it all. In case of values types, the variable stores the value directly and in case of reference types, it stores the reference to the variable (address). Other concepts like possibility of two variables referencing the same object are possible as in the case of C++.
A sample program to understand the types:
using System;
class ClassObj
{
public int num = 0;
}
class ClassTest
{
static void Main()
{
int x = 0;
int y = x;
y = 101;
ClassObj ref1 = new ClassObj();
ClassObj ref2 = ref1;
ref2.num = 999;
Console.WriteLine("Values: {0}, {1}", x, y);
Console.WriteLine("Refs: {0}, {1}", ref1.num, ref2.num);
}
}
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>csc D:\cstypes.cs
Microsoft (R) Visual C# .NET Compiler version 7.00.9466
for Microsoft (R) .NET Framework version 1.0.3705
Copyright (C) Microsoft Corporation 2001. All rights reserved.
C:\WINNT\Microsoft.NET\Framework\v1.0.3705>cstypes
Values: 0, 101
Refs: 999, 999
An interesting thing that I’ve observed is the method used to print the formatted output in Console.WriteLine
Console.WriteLine takes a variable number of arguments. The first argument is a string, which may contain numbered placeholders like {0} and {1}. Each placeholder refers to a trailing argument with {0} referring to the second argument, {1} referring to the third argument, and so on. Before the output is sent to the console, each placeholder is replaced with the formatted value of its corresponding argument.
Simple Basic Concept in C#
It is always better to understand these concepts with an example rather than trying to understand paragraphs of explanation.
Example:
class sharpTest
{
static void Main()
{
string s = "Sunil";
string t = string.Copy(s);
Console.WriteLine(s == t);
Console.WriteLine((object)s == (object)t);
}
}
Output:
True
False
Inference:
Two expressions of type object are considered equal if both refer to the same object, or if both are null.
Two expressions of type string are considered equal if the string instances have identical lengths and identical characters in each character position, or if both are null.
Type conversions are similar to C++. Implicit conversions like int to long are done without any loss of data. Explicit conversions are done with a cast expression.
Arrays in C#
As usual, single-dimensional and multi-dimensional arrays are supported.
// Creates a single-dimensional array of 5 elements
int[] arr = new int[5];
What is to be noted is that arrays are also reference types and hence have to be explicitly allocate the memory by specifying the size of the array.
// Some more arrays
int[,,] a3; // 3-dimensional array of int
int[][] j2; // "jagged" array: array of (array of int)
int[][][] j3; // array of (array of (array of int))
Type system unification
class Test
{
static void Main() {
Console.WriteLine(3.ToString());
}
}
All types including value types are derived from the type object. It is possible to call object methods on any value, even values of “primitive” types such as int.
Example:
class sharpTest
{
static void Main()
{
string s = "Sunil";
string t = string.Copy(s);
Console.WriteLine(s == t);
Console.WriteLine((object)s == (object)t);
}
}
Output:
True
False
Inference:
Two expressions of type object are considered equal if both refer to the same object, or if both are null.
Two expressions of type string are considered equal if the string instances have identical lengths and identical characters in each character position, or if both are null.
Type conversions are similar to C++. Implicit conversions like int to long are done without any loss of data. Explicit conversions are done with a cast expression.
Arrays in C#
As usual, single-dimensional and multi-dimensional arrays are supported.
// Creates a single-dimensional array of 5 elements
int[] arr = new int[5];
What is to be noted is that arrays are also reference types and hence have to be explicitly allocate the memory by specifying the size of the array.
// Some more arrays
int[,,] a3; // 3-dimensional array of int
int[][] j2; // "jagged" array: array of (array of int)
int[][][] j3; // array of (array of (array of int))
Type system unification
class Test
{
static void Main() {
Console.WriteLine(3.ToString());
}
}
All types including value types are derived from the type object. It is possible to call object methods on any value, even values of “primitive” types such as int.
Tuesday, April 05, 2005
C# versus VB.NET
Hi
many of our friends wanna know about this question, so i would like to answer this questions
Q: any advantages C# would have over Visual Basic (VB) in terms of the framework?
Answer: Regarding C# vs. Visual Basic, it really primarily comes down to what you already know and are comfortable with. It used to be that there was a large perf difference between VB and C++, but since C# and VB.NET use the same execution engine, you really should expect the same perf. C# may have a few more "power" features (such as unsafe code), and VB.NET may be skewed a bit more towards ease of use (e.g. late bound methods calls), but the differences are very small compared to what they were in the past.
Q: Okay, can we contrast C# with VB.NET? Questions usually come in the form of "I know you guys say VB.NET and C# let you do the same thing, but C# was designed for the CLR, so I don't believe you when you say VB.NET is just as good."
Answer: Regarding C# versus VB.NET, the reality is that programmers typically have experience with either C++ or VB, and that makes either C# or VB.NET a natural choice for them. The already existing experience of a programmer far outweighs the small differences between the two languages.
Q: Could you discuss the security of the config files. I have seen a lot of concern that since they are simple XML files, they can be hacked into easily.
Answer: We do block all access to the config files from remote users. However, I think the concern people have is whether a rogue user who gets access to the config file can modify and take over things. Note that this problem exists with ASP today as well, in that the metabase APIs can be written to, which would effectively do the same thing. However, there are some things that you can do to reduce this problem. Specifically, with ASP.NET we support the ability to "lock down" settings at a parent directory. For example, you might want to lock down the security identity of the worker process (i.e.: the username it runs under) at the machine level and then restrict sub-applications' abilities to override it.
Q: I've seen a lot of concern that data can be passed page to page (ASP to and from ASP.NET).
Answer: Since we really use standard Web techniques, passing info page to page should not be a problem. However, page to page in ASP and ASP.NET typically assumes services that are provided by each, such as session and application state. These services are not shared, and so you can't rely on them. I have a list of things you can do to ease migration of ASP code to ASP.NET.
1. Use only a single language within the ASP application. Don't intermix VBScript and JScript together in the same page (in general a bad programming practice with ASP, but also a migration issue for ASP.NET in that we now require only one inline <% %> language.
2. Explicitly declare all of ASP page functions within a
many of our friends wanna know about this question, so i would like to answer this questions
Q: any advantages C# would have over Visual Basic (VB) in terms of the framework?
Answer: Regarding C# vs. Visual Basic, it really primarily comes down to what you already know and are comfortable with. It used to be that there was a large perf difference between VB and C++, but since C# and VB.NET use the same execution engine, you really should expect the same perf. C# may have a few more "power" features (such as unsafe code), and VB.NET may be skewed a bit more towards ease of use (e.g. late bound methods calls), but the differences are very small compared to what they were in the past.
Q: Okay, can we contrast C# with VB.NET? Questions usually come in the form of "I know you guys say VB.NET and C# let you do the same thing, but C# was designed for the CLR, so I don't believe you when you say VB.NET is just as good."
Answer: Regarding C# versus VB.NET, the reality is that programmers typically have experience with either C++ or VB, and that makes either C# or VB.NET a natural choice for them. The already existing experience of a programmer far outweighs the small differences between the two languages.
Q: Could you discuss the security of the config files. I have seen a lot of concern that since they are simple XML files, they can be hacked into easily.
Answer: We do block all access to the config files from remote users. However, I think the concern people have is whether a rogue user who gets access to the config file can modify and take over things. Note that this problem exists with ASP today as well, in that the metabase APIs can be written to, which would effectively do the same thing. However, there are some things that you can do to reduce this problem. Specifically, with ASP.NET we support the ability to "lock down" settings at a parent directory. For example, you might want to lock down the security identity of the worker process (i.e.: the username it runs under) at the machine level and then restrict sub-applications' abilities to override it.
Q: I've seen a lot of concern that data can be passed page to page (ASP to and from ASP.NET).
Answer: Since we really use standard Web techniques, passing info page to page should not be a problem. However, page to page in ASP and ASP.NET typically assumes services that are provided by each, such as session and application state. These services are not shared, and so you can't rely on them. I have a list of things you can do to ease migration of ASP code to ASP.NET.
1. Use only a single language within the ASP application. Don't intermix VBScript and JScript together in the same page (in general a bad programming practice with ASP, but also a migration issue for ASP.NET in that we now require only one inline <% %> language.
2. Explicitly declare all of ASP page functions within a