Microsoft's techie

ASP.Net 4.0 New Feature - 1 : SEO improvement through Redirect Permanently

2011-06-06T05:43:00.000-07:00

ASP.Net 4.0 has added many features to its hat to cater various facilities to different user base. Permanent redirection feature helps in SEO. Before we understand more about the functionality let us look at the definitions of status codes sent to browser set by W3c.

10.3.2 301 Moved Permanently
The requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs. Clients with link editing capabilities ought to automatically re-link references to the Request-URI to one or more of the new references returned by the server, where possible. This response is cacheable unless indicated otherwise.
.
.
.
10.3.3 302 Found
The requested resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client SHOULD continue to use the Request-URI for future requests. This response is only cacheable if indicated by a Cache-Control or Expires header field.
.
.
.

To simplify when browser receives code 301 it understands that resource has been permanently moved to reported website and 302 is considered as temporarily. So when we use permanent redirection through code behind server sends code 301 in head so each subsequent requests are auto redirected to new URL without involving round trip.

Response.RedirectPermanent("/about.aspx");

This function has one overload same as Response.Redirect to tell to end the response.

Design Pattern - Daily Learning

2010-06-11T21:26:00.000-07:00

To begin with we write a game where ducks can swim and quack. We used OO inheritance:

One way was to create a virtual function in Duck class and override in Rubberduck class. But then again we realized that requirements keep changing and there is a new type of duck added called DecoyDuck which should neither flies nor quacks. And we will have many different types of duck to be added to the game in future behaving differently and we will be forced to override everytime.

So we thought of implementing an interface for fly and quack methods. Duck that fly and quack will implement that interface. So we have separated the behaviors that vary.

Later we wanted to ducks to fly in the game. If I add fly method to Duck class then all the ducks will start flying including Rubberduck which I don't want to fly.

Identify the aspects of your application that vary and separate them from what stays the same.

Based on the above principle, fly and quack are varying. So we'll pull out both the methods and create a new set of classes to represent each behavior.

To keep things more flexible we would want to assign behaviors to the instances of Duck class during run time and should be able to change it.

Program to an interface not an implementation

So based on the second principal just mentioned, we will create interfaces for the Fly and Quack.

So Duck class will look something like this

public class Duck

{

IFlyBehavior flyBehavior;

public void PerformFly()

{

flyBehavior.Fly();

}

public class MallardDuck : Duck

{

public MallardDuck()

{

flyBehavior = new FlyWithWings();

}

So now things are loosely coupled and cal be reused. What if I have to change a fly behavior at run time. It simple now, we just have a setter for flying behavior of duck in Duck class.

SetFlyBehavior(IFlyBehavior ifb)

{

flyBehavior = ifb;

}

Let us See how we will use setter

Duck d = new MallardDuck ();

d.PerformFly();

d.SetFlyBehavior( new FlyNoWay());

d.PerformFly();

We noticed that each Duck has a FlyBehavior to which it delegates its flying behavior.

So we are not inheriting their behavior but letting them change during runtime. Putting classes them together in such a way is called Composition.

Favor Composition over Inheritance.

So with these three principals, we have learnt first design pattern called Strategy

The Strategy Pattern defines a family of algorithms, encapsulates each one, and makes them interchangeable. Strategy lets the algorithm vary independently from the clients that use it.

Inheritance - Daily Learning

2010-06-08T01:14:00.000-07:00

I always wonder that most of the people don't realize the importance of virtual and override words in the function. Everytime I ask, many (8 out of 10) of them tend to answer that virtual function can be overridden by child class. When you don't define base class function as virtual and child class function as override then also it overrides. So here I am going to show the difference with the following example in Console App.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Inheritance
{
class Program
{
static void Main(string[] args)
{
CA ca = new CA();
CB cb = new CB();
CA cab = new CB();

ca.fun1();
ca.fun2();
ca.fun3();
ca.fun4();

cb.fun1();
cb.fun2();
cb.fun3();
cb.fun4();

cab.fun1();
cab.fun2();
cab.fun3();
cab.fun4();
Console.ReadLine();
}
}

public class CA
{
public void fun1()
{
Type type = GetType();
Console.WriteLine("CA: fun1");
}
public virtual void fun2()
{
Type type = GetType();
Console.WriteLine("CA: fun2");
}
public virtual void fun3()
{
Type type = GetType();
Console.WriteLine("CA: fun3");
}
public virtual void fun4()
{
Type type = GetType();
Console.WriteLine("CA: fun4");
}
}
public class CB:CA
{
public void fun1()
{
Type type = GetType();
Console.WriteLine("CB: fun1");
}
public void fun2()
{
Type type = GetType();
Console.WriteLine("CB: fun2");
}
public override void fun3()
{
Type type = GetType();
Console.WriteLine("CB: fun3");
}
public new void fun4()
{
Type type = GetType();
Console.WriteLine("CB: fun4");
}
}
}

It's out put is as follow

C# -Daily Learning

2010-06-04T11:06:00.000-07:00

Difference between ref and out parameter

a ref parameter should be assigned before they are called.
out are assigned by the called function itself.
out parameter is used to return more than one values from a function other than return object.
ref = Reference, when parsed to a method, the method references that original variable and doesnt create another instance. So if you make a change to a var parsed into that method when ref is used, it will affect the calling method

Learning C# - Everyday learning

2010-06-03T09:38:00.000-07:00

Namespaces can be nested. So I can have one namespace within another.
System is most frequently used namespace
Inside System namespace is class called Console, which contains static methods.

The datatypes are defined as classes, they are equipped with methods. ToString() is a common method for all the datatypes.

We can use pointers in C# but we have to mark the functions that use pointers as 'unsafe'

unsafe static void Main()

To read numbers from console window use Parse method.

 Number = int.Parse(Console.ReadLine());

Formatting numbers

Character		Used For
c	C	Currency values
d	D	Decimal numbers
e	E	Scientific numeric display such as 1.45e⁵
f	F	Fixed decimal numbers
g	G	General and most common type of numbers
n	N	Natural numbers
r	R	Roundtrip formatting
x	X	Hexadecimal formatting
p	P	Percentages

var Distance = 248.38782;
Distance.ToString("E") would result var into 2.483878E+002

var NewColor = 3478;
NewColor.ToString("X") would result var into D96

var HSalary = 22.74121
HSalary.ToString("c") would result var into $22.74

var HoursWorked = 35.5018473;
HoursWorked.ToString("F") would result var into 35.50

HTML CSS training

2010-06-03T00:58:00.000-07:00

Last week we had training on HTML CSS taken by Lakshminarayana. Training included on-board explaination, theory lectures, Hands-On as well as assessment (which I have not completed till i wrote this post). I am going to put some of the points that I learnt and found really useful which as a developer we tend to ignore or forget.
Specificity : It shows that how specific a selector is and based on the weight-age it assigns the value. Specificity is calculated as follow :
if Specificity is --> a b c d
then a i shows if it is inline style. if yes (a=1) and the specificity becomes highest and gets precedence over all other selectors.
b shows number of Id attributes in the selector
c is for class and pseudo classes
d is for number of elements

Box Model

You can define margin as either explicitly margin-left, margin-top
or you can give it as whole
margin: '10px 12px 6 px 4px';
where 10px is top margin, 12 is right and sequentially clockwise.

Similarly padding and border can be defined.
margin backgrounds are always transparent.

In CSS 2.1 horizantal margin never collapse but vertical may.

Vertical margins may collapse between certain boxes:

Two or more adjoining vertical margins of block boxes in the normal flow collapse. The resulting margin width is the maximum of the adjoining margin widths. In the case of negative margins, the maximum of the absolute values of the negative adjoining margins is deducted from the maximum of the positive adjoining margins. If there are no positive margins, the absolute maximum of the negative adjoining margins is deducted from zero. Note. Adjoining boxes may be generated by elements that are not related as siblings or ancestors.
Vertical margins between a floated box and any other box do not collapse (not even between a float and its in-flow children).
Vertical margins of elements that establish new block formatting contexts (such as floats and elements with 'overflow' other than 'visible') do not collapse with their in-flow children.
Margins of absolutely positioned boxes do not collapse (not even with their in-flow children).
Margins of inline-block elements do not collapse (not even with their in-flow children).
If the top and bottom margins of a box are adjoining, then it is possible for margins to collapse through it. In this case, the position of the element depends on its relationship with the other elements whose margins are being collapsed.
- If the element's margins are collapsed with its parent's top margin, the top border edge of the box is defined to be the same as the parent's.
- Otherwise, either the element's parent is not taking part in the margin collapsing, or only the parent's bottom margin is involved. The position of the element's top border edge is the same as it would have been if the element had a non-zero bottom border.
An element that has had clearance applied to it never collapses its top margin with its parent block's bottom margin.

Note that the positions of elements that have been collapsed through have no effect on the positions of the other elements with whose margins they are being collapsed; the top border edge position is only required for laying out descendants of these elements.
Margins of the root element's box do not collapse.

Margin width property can be difine in 2 ways, one through definite margin width and another is percentage. percentage value is defined based on width of the content (even margin-top also refers to width of content in case of percentage. so percentage of content's width is taken not the height)

salt marched the GIDS.Net

2010-04-20T03:43:00.000-07:00

The fresh morning, we headed towards beautiful place amidst city traffic. IISc, a dreamland for all GATE aspirants has been a perfect place to have such a summit that provides all the means to organize evnt and at the same time surrounded by in campus greenry. We entered the reception area, got our id, meal coupon and other goodies.

The entire day was heavily loaded with sessions from different technologies. I could see some microsoft techology evangelist, key note speakers walking around. some of the faces from speakers and developers I could easily recollect from last year conference at same place. Personally, I liked Stephen Forte's presentation last year and was looking forward to attend at least one of his sessions. Finally Idecided to attend his session on SQL 2008 R2 just after the lunch and it was very interesting. Another session that I liked most was "Hands on MVVM for WPF and silverlight" by Anoop from Sumeru. We had nice lunch with my faorite dessert "gulab jamoon" :). Though sessions were well distributed but still in each time slot I found more than one topic or speaker that I was interested in.
All in all it's been a lovely day so far before I finish my day at conference by attending last session. Good wrk done by saltmarch team.

GIDS.Net kicks off today

2010-04-20T02:57:00.000-07:00

What I learnt Today

2009-11-30T04:41:00.000-08:00

I thought of creating a series of what I learnt today. I feel almost everyday I learn something new and it gets slipped somewhere at the back of mind if I don't recall it. So its better to post it so that it will be a sort of revision for me and would be helpful to others. So I'll post my day to day learning under this post.

Today when I was working on Merging 2 databases and making them one, we had to define new constraints and keys . While defining new keys we found the following type of error coming.

The ALTER TABLE statement conflicted with the FOREIGN KEY constraint "FK__Grid__Page_ID__523BA32C". The conflict occurred in database "STATSONLINE", table "dbo.Page", column 'Page_ID'.

This error was caused when I ran the following query to give foreign key constraint.

ALTER TABLE Grid ADD FOREIGN KEY (Page_id ) REFERENCES Page(Page_Id)

After looking at the error one would guess that query is trying to define some foriegn key on the table 'Grid' which is already there and hence not allowing to overwrite that. At least I did think that way and started serching for all the Keys defined on the table. To my surprise there wasn't any such constraint define. Finally I concluded that It happens when this constraint can not be defined on the table because of inconsistent data. I had many grid records defined with the pages that are not there in page table. So it violates the basic requirement of foreign key.

About FK__Grid__Page_ID__523BA32C I feel it is the in memory name that server has given temporarily and then it checks all the records against this constraint and if it doesn't meet the criteria it throws aforesaid exception.

Microsoft .Net 2010

2009-11-29T23:12:00.001-08:00

It’s always been fun watching how Microsoft has eased the whole SDLC to promote RAD, with the release of their programming framework and tool. Same had happened with .Net 4.0 video series, spanning over a week, one hour every day ahs finished last Thursday under the guidance of Naresh Sharma. His inputs were definitely helping to understand the concept.
Our strategy to learn new technology is to learn elements of .Net 4.0 first and then divide the team into groups to dig into more specialized features. So far the exercise of watching videos has prepared a ground for the developer to know the basics. I’ll just brief the things we have learnt. And then more detailed about the topics will be covered in upcoming posts.
I’ll begin with the feature that I liked most ‘Managed Extensibility Framework’. I liked the ability to reuse the components already built. Using MEF .net applications are composed dynamically instead of compiling statically. It tackles the problem of software maintenance in a much better way by providing built in extensibility points that can easily be discovered, and which supports discovery of extension.
Another feature is Type Equivalence which fixes the pain re distributing Primary Inter-Op Assemblies. Version independence can be achieved using “Embed Interop Types” compilation option. Entity Framework 2.0 allows you to Model your application first before you design your database. MEF 2.0 actually designs the database for you based on your entities in the model. It makes fairly smart choices in defining Data Types and relationships. So developer always focuses on entities alone not on the mechanism of data persistence. C# 4.0 comes with the feature of named parameters. This features prevent you from the headache of writing multiple overload of same method. Parallel Extension in

Visual Studio 2010 supports Test Driven Development (TDD) by enabling you to write your tests first and then it generates the template for classes, functions and properties. Also debugging has been made deeper to look into calls within .net classes. One simple but exciting feature “Camel Case Search” is also very helpful, if your solution is having a large number of classes spanning across multiple projects. VS2010’s editor is also customized to have your own extension. Deploying an application in different environment has been made easier than ever by maintaining different configuration settings for different environment. UI functional testing is capable of automating Web and Windows application. It records all state of application automatically and run.
While talking about .Net 4.0, I can’t miss ASP.NET to talk about. 4.0 version allows you to control the client side id of controls. So instead of programming against some complex ids that are generated by .net 3.5 or earlier version (something like _dlGenControls__ctl0_CtrlPrintPageInstructions1_lblSubSection ) , Control ids can be defined. Javascript intellisense is more intelligent to list functions available. Mark up editing in ASPX page is also quicker with the features like easy tabbing, auto populating of controls with their short name etc.
Other than C#, ASP.Net and VS 2010; we also covered elements of F#. All in all, it was a good exercise to watch in a group and discuss than distributing videos to individuals and ask them to watch. So by the time you read this posting we would have divide the team for specialization and get them ready for post on the specialized topics.

First Program with WorkFlow (Part II)

2008-07-24T02:18:00.000-07:00

You need to see the previous post to begin with. Now we will add the code.

To do so, click on Solution Explorer’s View Code toolbar button to open the Workflow1.cs C# file for editing. In the constructor InitializeComponent is called. InitializeComponent is there in WorkFlow1.designer.cs where it initializes the events we inserted using designer. We will locate EvaluatePostalCode method in Workflow1.cs and insert the following code.

string USCode = @"^(\d{5}$)|(\d{5}$\-\d{4}$)";

string CanadianCode =@"[ABCEGHJKLMNPRSTVXY]\d[A-Z]\d";

e.Result = (Regex.IsMatch(_code, USCode) || Regex.IsMatch(_code, CanadianCode));

here e is an instance of ConditionalEventArgs, used to tell the IfElse activity which branch to take.

e.Result = true, means left branch is executed

To accept the incoming string, we add public property.

private string _code = String.Empty;

public string PostalCode

{

get{ return _code;}

set{_code = value;}

}

At this point our code will compile but no result. We need to add handlers for the conditional branches. Write following line of code in PostalCodeValid method.

Console.WriteLine("The postal code {0} is valid.",_code);

Similarly, handler for right branch in PostalCodeInvalid method.

Console.WriteLine("The postal code {0} is invalid.",_code);

This is all, workflow portion is complete. Now we’ll add code to Main method for startup.

You will see the following code in Main method:

WorkflowInstance instance = workflowRuntime.CreateWorkflow(typeof(PCodeFlow.Workflow1));

Replace it by following.

Dictionary wfArgs = new Dictionary();

wfArgs.Add("PostalCode", args.Length>0?args[0] : "");

WorkflowInstance instance = workflowRuntime.CreateWorkflow(typeof(PCodeFlow.Workflow1), wfArgs);

Autogenerated code would work fine, however we want to pass the postal code found on the command line so we have replaced it by our own code.

Now you can run it and type the following command pcodeflow 12345 and hit “Enter” key. You see the output as “The postal code 12345 was valid. You can check for invalid condition.

Woooo….w! Our first program is running.

First Program with WorkFlow

2008-07-17T01:37:00.000-07:00

Download .Net Framework 3.0 runtime components ( dotnetfx3setup.exe) and run the setup.
Install Windows SDK
Install Visual Studio Extension for Workflow.

Visual Studio 2005 Support for WF fall into 2 main categories:

a. Visual Editing – drag drop functionality

b. Templates – for adding workflow-based projects, it adds assemblies’ references.

As usual, we would create first ‘console-based’ workflow project. In Visual Studio open a new project. In project types pane expand Visual C#, click on Workflow and select “Sequential Workflow Console Application”. Clicking on “OK” creates basic project for you and bring up the workflow visual designer user interface. It will create 2 files for you.

i. Program.cs

ii. Workflow1.cs

In solution explorer you can select Workflow1.cs and click on toolbox.

Drop IfElse activity. We would use this to check whether the input string is a valid postal code or not? When you drop IfElse activity you will see the exclamatory sign that tells that you have not written the code for the decision and gives compile time error. Click on left branch go to properties and set condition property to “Code Condition”. And it will ask for the name of event that needs to be fired for evaluation. Type event name as EvaluatePostalCode in “Condition” Property (Child Property of Condition). Now drop the Code activity on the left branch to add code that will execute when EvaluatePostalCode returns true. Select property “ExecuteCode” and write PostalCodeValid.

So what Visual Studio 2005 has done, It has inserted events that will execute code that we will provide. The first event handler, EvaluatePostalCode, executes when the workflow needs to evaluate the test condition. The second event handler, PostalCodeValid executes when the left branch is taken.

Similarly we can add Code to right branch and name the event PostalCodeInvalid.

Windows Workflow Foundation - An Introduction

2008-07-09T04:53:00.000-07:00

Introduction

WF provides you with the multithreading capability without the hassle. Without WF you either execute your workflow tasks in the same thread that runs your UI or main process or you write multithreaded software yourself (It’s not so easy) and have a separate threads execute the process logic.

Comparing WF with Microsoft Biztalk and WCF

Orchestration is Biztalk’s term for workflow. You can use a Graphical Editor to lay out business processes, and some of these processes might even include external egencies, such as a trading partner, through external communications protocols. Communication with your trading partners is easy and seamless with BizTalk.

Biztalk is designed for inter application (multiple apps). WF, on the other hand, is designed to work at OS level and is therefore appropriate for integration into a single app within a single domain. But it doesn’t mean you can’t communicate with external processes and servers using WF, but WF’s primary focus is facilitating WF functionality within your app.

When, in a application, we change a given method’s signature, name etc, I must recompile all the software that that uses that method. So we use web service by changing our mentality from “use this method” to “use this service”. That is called SOA. Service based software is integrated using contracts and policy. It’s expected that services will morph and change, and the goal is to have dependent processes recognize changes and adjust accordingly. Contract identify what services are available. Policy describes how the services are to be used. When contracts or policies are changed, ideally service consumers automatically adjust and change as well

Actually, when contracts or policies change, things don’t magically fix themselves. In reality, service provider should communicate how many previous versions they’ll support and service sonsumer should update their code to most up-to-date version asap.

Though WF provides you with some basic tool to use XML web services, you can expose and consume web services. But WCF is much more powerful. Primary goal of WCF is to unify the programming model for all electronic processes, certainly second goal is to implement Internet standards for Web Services and allow you to build connection based SOA. If you require string SOA support, by all means use WCF.

Must know for Developers (Part -1)

2008-07-08T23:37:00.000-07:00

I would like to discuss essential things that a developer must be familiar with. In todays competitive world, as more technologies are emerging and so are technology terms. If you look around the internet you will find so many new things that people are talking about. If you don't know the meaning of those terms you'll be not understanding what they are talking about. So I'll be posting the definitions and very very high level of understanding on those terminologies. After that as and when I'll start different blogs for a particular type of technology for detail discussion.

Let us start with
1. Web service

Web service is a performing remote method calls over HTTP.

A software system designed to support inter operable machine to machine interactiona over network.

Web services are frequently just Web APIs can be accessed over a network, such as the Internet, and executed on a remote system hosting the requested services
In Simple terms

You want to use some function e.g. a function DayDiff which takes two dates as parameters and results back the difference of days between both the dates. If somebody has already written the same function, you would not like to reinvent the wheel. You would like to use it. Web service is the way through which he can publish (or expose) this function over the internet and you can discover it and use it in your application. Though lot of things are going on behind the hood. But for introduction purpose you can skip all that.

2. SOAP

On your way to web service you will come across this term. It stands for Simple Object Access Protocol. This is a protocol for exchanging XML based messages over HTTP. SOAP forms the foundation layer of the web services protocol stack providing a basic messaging framework upon which abstract layers can be built.

As a layman's example of how SOAP procedures can be used, a correctly formatted call could be sent to a Web Service enabled web site - for example, a house price database - with the data ranges needed for a search. The site could then return a formatted XML document with all the required results and associated data (prices, location, features, etc). These could then be integrated directly into a third-party site

3. Mashup

Mashup is a web application that combines data from more than one source into a single integrated tool.

Creating a new web service by combining two or more services available that was not originally provided by either source.

There are basically three types of mashups

consumer mashups

Consumer mashups combine data elements from multiple sources, hiding this behind a simple unified graphical interface

data mashups

A data mashup mixes data of similar types from different sources, for example combining the data from multiple RSS feeds into a single feed with a graphical front end.

Enterprise mashups

usually integrates data from internal and external sources

Business mashups

A business mashup is combination of all above types of mashups, focusing on both data aggregation and presentation, and additionally adding collaborative functionality, making the end result suitable for use as a business application.