Why should we hire you?

This is another common question asked in your interview. This question deals with your ability to market yourself with the experience and skills you have.
The interviewer is asking this question to find out how can your skills and experience be a value add for the job you are being interviewed for.

Answers that would get the interviewer's attention:
1. I have three years of experience in this technology and my skills enables me to develop better products in less time

2. I have what it takes to fill the requirements of this job - solve customer problems using my excellent customer service skills.

3. I have the experience and expertise in the area of customer support that is required in this position.

This is the time to let the interviewer know what you can do for them and why they should listen to what you have to offer. The more detail you give, the stronger your answer will be. This is not a time to talk about what you want. It is a time to summarize your accomplishments and relate what makes you unique and therefore a viable fit for this position.


Look at the job description. Find out requirements of the job? Make a list of these requirements. List your skills and think of two or three key qualities you have to offer that match each requirement that the employer is seeking.

The following are the other ways of asking the same question:
What can you bring to this position?
What can you bring to the table if selected?
Why do you think you are qualified for this job?  

Tell me something about yourself ?

This is the most common and very first question usually asked in any interview. When you answer this question you usually have to tell about the following:

Educational Qualifications: When you talk about educational qualifications, don't talk about percentages unless they are very good. If you have made any achievements like topping college academics or secured a gold medal make sure you tell about it.

Family Background: Donot spend too much of time here. Let the interviewer know your father's and mother's profession and how many siblings you have.

Hobbies/Interests: This is very important section and be prepared for follow up questions. If you say my hobby is reading books. Interviewer might ask a followup question like, what type of books you usually read. If you say I read fiction books. The interviewer might ask you, Who is your favourite author.

So be very careful when you are making up hobbies. It is better if your hobbies add value for the type of job you are doing. For example if you are going for a software engineer interview, you can say browsing internet as one of the hobby. If a software engineer has good browsing skills he might find solutions online quickly and solve the problem at hand in less time. When you say browing as one of your hobby, be prepared for the follow up interview questions like, What do you usually browse on the internet? What is your favourite website? Who is your favourite technical article writer? 


Strengths: Tell interviewer about your strengths with example. Examples of strengths are listed below. Make sure you back up each strength with an example from your past experience.

Hard Working in nature.
Dedication.
Commitment.
Good Team player.
Communication Skills
Problem solving skills
Taking Initiatives
Beging Pro-active
Design Skills

Weakness: When ever you say you have a weakness, make sure you also have a plan and working on it to over come your weakness.

Too invloved: Some times when there is a technical issue or a problem I tend to work continuously until I fix it without having a break. But what I have noticed and, I am trying to practice is that, taking a break away from the problem and thinking outside the box or taking suggestions will assist you in identifying the root cause of the problem sooner.

Over confident: Very rarely I become over confident, especially when a simple task is given, I get to solving the issue without spending much time planning. So I am working on applying the 80/20 principle of planning and implementation. Spend 80% of my effort and time in planning and 20% on implementation. 

Why are you looking for a change ?

When answering this question please make sure not to talk anything bad about your current organisation, Manager or your peer. What ever may be the reason why you left your present job, don't speak badly about your previous employer. The interviewer may think, you will talk bad about his company next time you're looking for another job.

The following are some of the reasons you shouldn't be giving for quitting your current job:
1. They didn't pay you enough.


2. Odd shift timings.


3. You did not like the management.


4. This new job offer pays much more than what you are getting now.


5. You are fired for poor performance or bad code of conduct. 

Answers that could get interviewer the attention:
1. My organisation is very small and I have already spent 3 years and as there is no scope for growth with my current employer and I'm ready to move on to a new challenge.


2. I'm looking for a bigger challenge and to grow my career and I couldn't job hunt part time while working. It didn't seem ethical to use my former employer's time.


3. I am relocating to this area due to family circumstances and left my previous position in order to make the move.


4. I am interested in a new challenge and an opportunity to use my technical skills and experience in a different capacity than I have in the past.


5. I was looking for a position like this which is an excellent match for my skills and experience and I am not able to fully utilize them in my present job as there is very limited scope for growth.

Other ways of asking the same question:
1. Why are you leaving your job?

2. Why did you leave your job?

3. What made you leave your current job?

Branching and Merging with TortoiseSVN || Merge Branch with Trunk || Delete a Branch ||

Overview

The discussion below assumes that you have a Subversion repository that uses the standard trunk/branches/tags structure. In other words, a repository at http://site.com/project with trunk, branches, and tags subdirectories.

I’ll also assume that you have already checked out a local working copy of trunk, and that you’ve already created an Eclipse project using this working copy.

When you want to work on a new branch you’ll follow these general steps using Subclipse, which are described in more detail below:
1-Create a new branch and switch to it
2-Develop in your branch, periodically merging the latest changes from trunk into your branch
3-When your development is complete, merge changes from your branch back into trunk
4-Delete your branch

Switch

Your local working copy reflects some directory in the remote Subversion repository. If you initially checkout trunk, then your working copy reflects trunk. If you initially checkout a branch, it reflects that branch. Using the svn switch command you can have Subversion modify your working copy to reflect another directory in the repository. Switching may not sound that exciting but it’s key to branching and merging, as you’ll soon see.

First off, ensure that your working copy has no local changes. Either commit your changes or revert them.

Next, right-click your project in Eclipse’s Project Explorer, select the Team submenu, and click the Switch to another Branch/Tag/Revision… item. All of Subclipse’s actions are in this Team menu, so from now on I’ll refer to specific actions like Team > Switch to another Branch/Tag/Revision.

In the To URL field, you specify the URL of the repository directory you want to switch your local working copy to. If your working copy initially reflects http://site.com/project/trunk, you could specify a branch as http://site.com/project/branches/somebranch. Generally you’ll want to leave all of the other options in this dialog box as they are.

Create a new Branch

Creating a new branch is almost trivial. First, switch your local copy to trunk (if it’s not already trunk). And again, make sure you have no local changes.

Next select Team > Branch/Tag… and specify http://site.com/project/branches/yourbranch in the Copy to URL field. This will create a branch named yourbranch.

Click Next and leave HEAD revision selected. Click Next again, enter a commit message like “Created the yourbranch branch”, check the “Switch working copy to new branch/tag” checkbox, and click Finish.

That’s it! You’ve created your new branch in the repository and switched your working copy to it. Now you can implement your major new features in your branch and commit them to subversion without affecting trunk.

This is assuming you have your code checked in to the trunk directory and have a standard SVN structure of trunk, branches and tags. There are a number of developers who prefer to develop solely in a branch and never touch the trunk, but the process is generally the same and you may be on a small team and prefer to work in the trunk and branch occasionally.

There are three steps to successful branching. First you branch, then when you are ready you need to reintegrate any changes that other developers may have made to the trunk in to your branch. Then finally when your branch and the trunk are in sync, you merge it back in to the trunk.


1 -Right click project root in Windows Explorer > TortoiseSVN > Branch/Tag

2 -Enter the branch label in the ‘To URL’ box. For example /branches/1.1

3 -Choose Head revision
 4-Check Switch working copy
5-Click OK
6 -Make any changes to branch

 7- Make any changes to trunk

8 - Commit any changes

For this example I copied the project to another location prior to branching and made changes to that using Notepad++. Then committed it to SVN, as this directory is mapped to the trunk, that is what gets updated.


Merge Trunk into a Branch

While you’re working on your branch, you should periodically merge the latest version of trunk into your branch to make sure you’re not straying too far away.  Eventually, you’ll also need to do this as the last step before merging your branch back into trunk, to ensure you won’t cause any conflicts with trunk.

First you’ll need to switch your working copy to your branch, if necessary.  Subversion will merge the changes from trunk into your working copy, and then you’ll commit your working copy to your branch to fully integrate the changes from trunk.  So it’s vital that you start with your working copy as a mirror of your branch.  And again, ensure you have no local changes.


1- Right click project root in Windows Explorer > TortoiseSVN > Merge

2 - Choose ‘Merge a range of revisions’

  

3- In ‘URL to merge from’ choose your trunk

4- Click Next, then the ‘test merge’ button. This will highlight any conflicts. Here we have one conflict we will need to resolve because we made a change and checked in to trunk earlier

5- Click merge. Now we have the opportunity to edit that conflict

6-This will open up TortoiseMerge which will allow us to resolve the issue. In this case I want both changes.

7- Perform an Update then Commit

8- Reloading in Visual Studio shows we have all changes that have been made to both trunk and branch.

Merge Branch with Trunk


When you’ve finished development in your branch, you need to merge your branch changes back into trunk, so everyone else can share in the glory of your awesome new feature.  This is usually where developers turn pale and run away, but fear not; Subclipse will guide you through.

Make sure you only perform this merge when you are completely finished with your branch!  After merging your branch into trunk, you will no longer be able to use your branch.  In fact, you should delete your branch after merging it into trunk (see next section).

First, merge trunk into your branch and commit any changes to your branch, as described in the previous section.  We need to make sure your branch is consistent with trunk before merging it back.

Next, switch your working copy to trunk.  Remember that Subversion merges changes into your working copy first, and then you commit them back to the repository.  So Subversion will apply your branch changes to your working copy of trunk, and then you commit those changes to trunk.

1-Switch working copy by right clicking project root in Windows Explorer > TortoiseSVN > switch

2- Switch to the trunk then ok



 
3- Right click project root in Windows Explorer > TortoiseSVN > merge

4- Choose ‘Reintegrate a branch’

5- In ‘From URL’ choose your branch then next

Click ‘Test merge’, this shouldn’t show any conflicts

Click Merge
Perform Update then Commit

Open project in Visual Studio, we now have all changes.

So there we have it we are connected back to the trunk and have all the updates merged.


Delete a Branch

As previously mentioned, after merging a branch into trunk, the branch can no longer be used.  Subversion keeps track of merges using the svn:mergeinfo property.  Because of the way it uses this property, once a branch is merged into trunk it can no longer be involved in merges properly.  For the full story, please consult the last few paragraphs of this section on branching and merging.

Subclipse does not provide a way to delete an entire branch, so you’ll need to just run this command manually:

svn delete http://site.com/project/branches/yourbranch -m "Removing completed branch"

Hosting an ASP.NET Web Forms Application on Windows Azure

http://www.asp.net/web-forms/tutorials/deployment/deployment-to-windows-azure/hosting-an-aspnet-web-forms-application-on-windows-azure

SQL Server Optimization Tips

In this article we discuss about how to optimize the SQL Server with simple tips.


Use views and stored procedures instead of heavy-duty queries.
This can reduce network traffic, because your client will send to server only stored procedure or view name (perhaps with some parameters) instead of large heavy-duty queries text. This can be used to facilitate permission management also, because you can restrict user access to table columns they should not see.


Try to use constraints instead of triggers, whenever possible.
Constraints are much more efficient than triggers and can boost performance. So, you should use constraints instead of triggers, whenever possible.


Use table variables instead of temporary tables.
Table variables require less locking and logging resources than temporary tables, so table variables should be used whenever possible. The table variables are available in SQL Server 2000 only.


Try to use UNION ALL statement instead of UNION, whenever possible.
The UNION ALL statement is much faster than UNION, because UNION ALL statement does not look for duplicate rows, and UNION statement does look for duplicate rows, whether or not they exist.


Try to avoid using the DISTINCT clause, whenever possible.
Because using the DISTINCT clause will result in some performance degradation, you should use this clause only when it is necessary.


Try to avoid using SQL Server cursors, whenever possible.
SQL Server cursors can result in some performance degradation in comparison with select statements. Try to use correlated sub-query or derived tables, if you need to perform row-by-row operations.


Try to avoid the HAVING clause, whenever possible.
The HAVING clause is used to restrict the result set returned by the GROUP BY clause. When you use GROUP BY with the HAVING clause, the GROUP BY clause divides the rows into sets of grouped rows and aggregates their values, and then the HAVING clause eliminates undesired aggregated groups. In many cases, you can write your select statement so, that it will contain only WHERE and GROUP BY clauses without HAVING clause. This can improve the performance of your query.


If you need to return the total table's row count, you can use alternative way instead of SELECT COUNT(*) statement.
Because SELECT COUNT(*) statement make a full table scan to return the total table's row count, it can take very many time for the large table. There is another way to determine the total row count in a table. You can use sysindexes system table, in this case. There is ROWS column in the sysindexes table. This column contains the total row count for each table in your database. So, you can use the following select statement instead of SELECT COUNT(*): SELECT rows FROM sysindexes WHERE id = OBJECT_ID('table_name') AND indid < 2 So, you can improve the speed of such queries in several times.


Include SET NOCOUNT ON statement into your stored procedures to stop the message indicating the number of rows affected by a T-SQL statement.
This can reduce network traffic, because your client will not receive the message indicating the number of rows affected by a T-SQL statement.


Try to restrict the queries result set by using the WHERE clause.
This can results in good performance benefits, because SQL Server will return to client only particular rows, not all rows from the table(s). This can reduce network traffic and boost the overall performance of the query.


Use the select statements with TOP keyword or the SET ROWCOUNT statement, if you need to return only the first n rows.
This can improve performance of your queries, because the smaller result set will be returned. This can also reduce the traffic between the server and the clients.


Try to restrict the queries result set by returning only the particular columns from the table, not all table's columns.
This can results in good performance benefits, because SQL Server will return to client only particular columns, not all table's columns. This can reduce network traffic and boost the overall performance of the query.



Summary for SQL Server Optimizations


Use Indexes
avoid more number of triggers on the table
avoid unnecessary complicated joins
correct use of Group by clause with the select list
Do Denormalization if required

how to make image bright and how to change text color dynamically

There are some situations where you need to change the content display dynamically. Like, you have to change font color and background color of your text or you have to make image bright. You can do these things by applying styles dynamically through javascript.



Here I gave you a solution to fulfill such type of requirement by using jQuery functions. We are using jQuery mouseover() function to highlight text or image on your webpage whenever we place mouse on it.



Below is the code to make text or image highlight whenever we place mouse on it.



<html>
<head>
<title>highlight the text and image dynamically using jQuery</title>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$('#parent').mouseover(function() {
$('#child1').css({
'background-color': 'green',
'font-weight': 'bold',
'color': 'red'
});
$('#child2').css({
'background-color': 'cyan',
'font-weight': 'bold',
'color': 'blue'
});

$('#img1').css({
'opacity':1.0
});
});

$('#parent').mouseout(function() {
$('#child1').css({
'background-color': 'white',
'font-weight': 'normal',
'color': 'black'
});

$('#child2').css({
'background-color': 'white',
'font-weight': 'normal',
'color': 'black'
});

$('#img1').css({
'opacity': 0.4
});
});

});
</script>
</head>
<body>
<div id="parent">
<div id="child1">this text from first child</div>
<div id="child2">this text from second child</div>
<img src="img1.jpg" id="img1" style="opacity:0.4" />
</div>
</body>
</html>



Here we have two <div> tags whose id's are child1, child2 and one <img> tag whose id is img1 with in parent <div> tag whose id is "parent".



We are applying jQuery mouseover() function to the parent <div> tag by using $('#parent').mouseover(function() { }. Within this function we are applying our required properties to different elements.



$('#child1').css({
'background-color': 'green',
'font-weight': 'bold',
'color': 'red'
});
$('#child2').css({
'background-color': 'cyan',
'font-weight': 'bold',
'color': 'blue'
});


will change the font color and background color of our two <div> tags to our required colors whenever we place mouse on it.



$('#img1').css({
'opacity':1.0
});



will make the image bright whenever we place the mouse on it.



Here we are also using the jQuery mouseout() function to roll back the changes of our elements.



$('#parent').mouseout(function() {
$('#child1').css({
'background-color': 'white',
'font-weight': 'normal',
'color': 'black'
});

$('#child2').css({
'background-color': 'white',
'font-weight': 'normal',
'color': 'black'
});

$('#img1').css({
'opacity': 0.4
});
});



will change the text font color, background color to black, white and will make the image blurred whenever mouse out from the content.

Apply CSS styles using jQuery

Here I am explaing how to apply CSS styles using jQuery. It is simple to apply styles using jQuery.



<html>
<head>
<title>This is jquery example for applying bold and italic for given elements</title>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$('p').addClass('boldtext');
$('#pid').addClass('italictext');
});
</script>
<style type="text/css">
.boldtext
{
font-weight:bold;
}
.italictext
{
font-style:italic;
}
</style>
</head>
<body>
<p>This is jquery example to make text as bold by applying class name to 'p' element itself</p>
<p id="pid">
This is jquery example to make text as italic by applying class name to 'p' id
</p>
</body>
</html>



In the above code we have two <p> tags. We make the these <p> tags text bold and italic bys using jQuery as given below.



$('p').addClass('boldtext');

$('#pid').addClass('italictext');



In the first line we make the all <p> tags text bold by applying "boldtext" CSS class to $('p'). $('p') means we are accessing all <p> tags.



In the second line we make the HTML tag texts whose id is "pid" as italic by applying "italictext" CSS class to $('#pid'). $('#pid') means we are accesing the HTML tags whose id is "pid".



Place all above HTML code in a HTML file and open it in any browser. You can find that all text in bold and only second line is in italic because we did all <p> tags text in bold by using $('p').addClass('boldtext') and we apply the italic style to second <p> tag only by using $('#pid').addClass('italictext').



Some times you have to apply different styles to alternative elements. For example, if you have some div tags and you need to apply different styles to alternative elements. For this type of requirement jQuery provides good solution as shown below.



<html>
<head>
<title>This is jquery example for applying the styles for alternative elements</title>
<script type="text/javascript" src="jquery.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$('div:odd').addClass('boldtext');
$('div:even').addClass('italictext');
$('p:eq(2)').addClass('italicbold');
});
</script>
<style type="text/css">
.boldtext
{
font-weight:bold;
}
.italictext
{
font-style:italic;
}
.italicbold
{
font-weight:bold;
font-weight:bold;
}
</style>
</head>
<body>
<div>This is jquery example to make odd div tags bold and even div tags italic by applying two class names to 'div' element itself</div>
<div>This is jquery example to make odd div tags bold and even div tags italic by applying two class names to 'div' element itself</div>
<div>This is jquery example to make odd div tags bold and even div tags italic by applying two class names to 'div' element itself</div>
<div>This is jquery example to make odd div tags bold and even div tags italic by applying two class names to 'div' element itself</div>
<div>This is jquery example to make odd div tags bold and even div tags italic by applying two class names to 'div' element itself</div>

<p>This is jquery example to make 3rd 'p' tag text as bold and italic</p>
<p>This is jquery example to make 3rd 'p' tag text as bold and italic</p>
<p>This is jquery example to make 3rd 'p' tag text as bold and italic</p>
<p>This is jquery example to make 3rd 'p' tag text as bold and italic</p>
<p>This is jquery example to make 3rd 'p' tag text as bold and italic</p>

</body>

</html>



As shown above, we apply the different styles for alternative div tags by using below jQuery code.



$('div:odd').addClass('boldtext');
$('div:even').addClass('italictext');



$('div:odd').addClass('boldtext') means "boldtext" CSS class added to odd number div tags.

$('div:even').addClass('italictext') means "italictext" CSS class added to even number div tags.



The above HTML code also includes one more functionality. That is $('p:eq(2)').addClass('italicbold'). $('p:eq(2)') represents the 3rd <p> tag element of all <p> tags in the HTML code. "eq" is the jQuery function, it will take index of the elements. In jQuery index starts from 0. Here we are making 3rd <p> tag text as italic and bold by applying "italicbold" CSS class to it.

How to find the right balance in between functionality and technology

The fundamental goal of each software developer is to build and deliver the right software that satisfies their customers. A software developer that wants to succeed, must be a professional focusing on a positive outcome of the project. He needs to find the right balance between building the right software and building the software right.

“There is only one boss. The customer. And he can fire everybody in the company from the chairman on down, simply by spending his money somewhere else” – Sam Walton

Focus on result

We need to understand that our customers’ problems are our challenges. We need to make sure that we addresses our customer’s needs. More importantly, we need to be able to respond and adapt quickly to changing situations, “whether it’s a wave  or a design that breaks sooner than expected”. This is how it works and we need to get used to it. We need to change the way we treat our customers, because development has to be a partnership between the customer and the development team.
Not to lose focus, we always need to make a valuable judgment about what is really important. We shouldn’t make all the decisions about a project ourselves, just because we know the most about the application. Let customers decide, especially when it is critical to their business.

Code quality isn’t the highest aim

Realizing good code quality and using best practice coding techniques to build the software right are important components of a successful project. But we should not forget that the cleanest code and the best architecture are not sufficient to build a successful solution which will be accepted by the client.
Developers tend to apply the best practices and/or design patterns to their projects. However,  in many cases we do this without considering whether this is actually needed. By applying patterns and best practices we tend to forget why they were created and when we should apply them in the first place. As a result they become anti-patterns that ultimately produce more bad consequences than beneficial results and isn’t that what we usually try to avoid?

Simplicity before beloved complexity

Simplicity is the key. We tend to over complicate simple problems and build complex solutions where it’s not needed. Most programs work best when kept simple. And simplicity is not only about the code; it is also about the design and architecture. Following the “Keep it simple, Stupid!” principle, we will end up with more efficient and high quality software.
We are obsessed by the need to use the latest technology, just because it is new. We shouldn’t make design decisions based on our own technology excitement. We should think whether the technology or application framework really solves the problem. A blindly chosen solution may have a negative impact on the project. We need to realize this each time when we are tempted by the newest technology or an application framework.

Striving for excellence

One of the key concepts of a successful software developer is striving for excellence. Software developers have to continuously improve their development process, skills and knowledge. The successful software developer learns not only coding techniques or technology but he also learns how to understand the (changing) customer business’ needs. He gains the ability to make proper decisions and find the right balance between functionality and technology.

Top 4 qualities of a good software developer

Have you ever wondered whether you can consider yourself a good software developer? If so, you probably also wondered what it means to be a good software programmer. What are the skills of a good software engineer? What are the differences between the bad and the good one? Is this just a matter of experience? Is this connected with knowledge and practice or rather with some inborn abilities? How to become a good software developer? Let me share with you my definition of a good programmer.

1. Analytical mind

There is no strict definition of an analytical mind. One thing is for sure: if you have an analytical mind you are able to think, observe data, remember and basing on these activities, resolve problems.

Unfortunately, this is the most crucial and needed skill of a good software developer. Why “unfortunately”? Well this means that not everybody can become a good software developer, even if they really struggle. Having analytical mind is to a big extend an inborn ability. If you do not possess this skill it is better to change the field of interest.

Solving many algorithmic and logic problems can increase the basic level of analytical thinking ability. However, every person has their own border (“maximum level” – like in RPG games) which can’t be exceeded.

2. Big-picture perception of a software

Creating software is like playing chess – to win you need to predict a few moves ahead. You should not only look at the presence but also into the future while programming. To be a good software developer you can’t only be focused on a small piece of software that you are implementing. You don’t only need to know how to implement something, but also why. You need to see the software as a whole not just as the small part you are currently working on. You need to understand the impact of your small piece on the whole. All in all, you simply need to see the bigger picture.

3. Business oriented approach to software development

In my definition of a good software developer, it is not enough to be technically oriented. You can be a good coder and your code can be of a really high quality, but still you won’t manage to understand and satisfy your customers’ needs. If you are not business oriented, it can potentially cause a lot of problems: misunderstandings, usability lacks or late changes in the functionality.

So, what does it mean to be a business oriented software developer? There are many factors that influence this feature of a developer, but in my opinion the most relevant are the below ones:
Understanding software from a business perspective
Appreciation of client’s needs
The ability of converting business problems into technical solutions
The ability to cooperate and understand people from non-technical stuff

4. Teamwork eagerness
A good software developer is not a person who sits for the whole day in front of the computer and codes. If a project is supposed to be successful, the communication inside the team is crucial. Exchanging thoughts, ideas, knowledge and experience can boost the efficiency and the quality of the solution. A developer who is not eager or able to communicate with other team members will not be able to fit in the team and in the process of developing software. I am aware that there are many very introverted developers who are doing really a great job and produce high-quality code. Yet in Agile, which is more and more common amongst IT companies, pure coding is not enough. Communication inside a team is one of the major keys to success.
Agile World needs good programmers

The above definition of a good software developer wouldn’t be applicable several years ago. If we weren’t agile, probably any good coder could be considered a good developer. But we are. Nowadays the IT world needs good Agile software developers who are able to analyze problems, see them from a broader perspective, are business oriented and eager to work in teams. Without them IT projects could not be handled by means of Agile methodology. Agile manifesto would become just a set of insignificant principals, not used by anyone.

What is your opinion on this subject? Do you think there are more abilities and skills that are required to be a good software developer? Is your definition of a good programmer different from the one displayed above? Feel free to share your own opinion below.

Start learing in MVVM ( silverlight or WPF Link)

OK, Lots of confusion around this pattern. I am also trying to wrap my head around this pattern and wanted to present what I have learned so far as well as my favorite links on the subject. I’m also working on a sample program that is from start-to-finish.
Model View ViewModel is usually called:

• MVVM 
• PresentationModel
• or just the plain ViewModel

1. It is just an architectural pattern for Silverlight of WPF.
2. It is designed to allow Designers to focus on the user experience instead of the business logic. 
3. It’s been around since 2005, but has just now taken off because of the success of WPF/Silverlight.
4. UI Unit Testing

So what is it and why is it so scary for a beginner.

Model- A class file
View – Usually a user control
ViewModel – Another class file : Your user control will get its data from the ViewModel. Please see the image below:



Image taken from orbifold.net – please don’t sue me. =)

I am planning on creating an application that shows you how to build it from start/finish. If you can’t wait on mine, here is a silverlight MVVM app that contains a full project using the pattern. Stay tuned!

Articles for more information:

WPF Apps With The Model-View-ViewModel Design Pattern by Josh Smith.

Introduction to Model/View/ViewModel pattern for building WPF apps

Advanced MVVM Book (Cost $10 but was written by Josh Smith)

MVVM – It’s Not Kool-Aid*

Videos for more information about the pattern:

Hands-On Model-View-ViewModel (MVVM) for Silverlight and WPF –recommended to watch the one on SilverLight first.

MVVM, a WPF UI Design Pattern - Essential Edition

Libraries of classes useful when building applications based on the MVVM philosophy.

MVVM Foundation
MVVM Light Toolkit

Mistakes to Avoid as a Web Developer

For all web developers, it is extremely important to give the best service they possibly can in order to make sure things are done correctly. However, it sometimes becomes an often occurrence that developers will make the same mistakes and that could send the whole project off course and force you to take longer than needed. This off course means more money being spent and time being lost that could be used on other stages.


Certain mistakes are common for developers, whether they are freelance or working for a firm. Avoiding these mistakes can help save you, your company and your client time and money no matter which capacity you’re working in. Here are a few tips to avoid mistakes in order to be successful and increase your reputation in the web developing world.

Keep the Lines of Communication Open

One of the main problems that many developers experience is the inability to communicate with clients or the “higher-ups” in order to come together on wants and needs when planning the web development. Clients and firms don’t always have a full understanding on what you as a developer are capable of and what you can use. Help make things easier and clearer for the clients and yourself by giving an idea of what can be done and let them fill out the remaining information in order to make things go smoothly.

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Understand the Size of Project

Research is such an important part of developing in terms of understanding exactly what you will need in order to complete any project you’re about to work on. This is the time to learn and inform clients or firms of budget, timeline and any other needs that you will have to have to complete the project with no problems. Giving the clients and firms a better idea will also keep them from having you make the next mistake.

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It’s a Marathon, Not a Sprint

Clients and firms, of course, would love to have all of their projects done fast, but that could come at the expense of having everything done right. Do not allow the clients or firms to rush you through any stage of the project whether it is planning or the actual developing so that you can make sure everything is in working order when you’re done with the project. This is where coming up with a pre-planned strike and numbers (budget, time) comes in complete handy because those that are expecting your projects won’t apply unrealistic numbers on you.

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Know your Role

As a web developer, it is crucial that you understand that you are exactly that; a web developer. You are not a project manager, nor do you hold any other position. Your job is to develop and taking on any other responsibilities past that could result in you losing track of what you’re main objective is, causing a problem with your time and budget constraints.

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Test, Test, Test

One of the biggest mistakes is for web developers to push the project without running multiple tests on multiple platforms and doing so alone. Different browsers, PCs, Mac computers, mobile; these are all different platforms to test on and enlisting some help will speed up the process and have a multiple set of eyes on everything just in case you miss something.
Be sure to use these tips when starting any project to avoid delays and make sure these mistakes don’t creep up on you.

JavaScript Mistakes You Must Avoid

If you are new to JavaScript and you write raw JavaScript or use any framework (jQuery, Mootools, Dojo, YUI) with it, you must avoid few mistakes. Actually these are my experiences when I was learning JavaScript.

Equality Operator

You may know that in js, two operators are used for comparing values. First is == (two equal signs). This operator compare the values but it doesn’t compare the data type of operands. For example if first operand is 1 and the second is true, the result will be true.

if( 1 == true ) { //this code will run }

Here are more examples.

1 == "1" //true "true" == true //false 1 == true //true "0" == 0 //true "" == 0 //true " " == 0 //true "Str" == false //false "Str" == true //false

Some of the results are unexpected specially for those who don’t know how JavaScript evaluates == operator. Actually every operand (no matter what data type it has) is converted to Number data type before comparison.

Consider the first example (1 == “1″). The first operand is already a number so no conversion occurs. Second operator is string so it’s converted or parsed to number. Now the second operator “1″ (string) is converted to 1 (number).

In the second example (“true” == true) is false because if the string contain characters other than digits, convertion to number will return NaN which means Not a Number. If anything is compared with NaN, comparison will always return false.

You can check what value will be returned after conversion to number using the Number constructor. Following are some tests in Firebug.



Now you maybe wondering how === operator works. Equality operator (with 3 equal signs) in JavaScript compare not only the value of operands, but also the data type. If the data type of operands is different, it will always return false. Both the data type and value of operands must be same in order to make the condition true.

4 === 4 //true "2" === 2 //false 1 === true //false "true" === true //false

Not Assigning null to Reference Types

It’s common mistake that many js developers don’t assign null value to variables of reference types (object or Array) when there use is finished. Take a look at following example.

var arr = [1, 2, 3];   //perform some processing on arr   //assign null to arr when its use is finished arr = null;

The benefit of assigning null to reference types is that the garbage collector of js engine automatically reclaims the memory used by that variable. Remember that this is specially important for variables whose scope is large like global variables. Local variables are automatically destructed when they are out of scope (specially js engines with Mark and Sweep garbage collector).

Reference Variable Initialization

Never try to initialize multiple reference variables (like object and array) in a single assignment statement. This can be better understood using an example.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

var arr1 = [1, 2, 3] , arr2 = ['a', 'b', 'c'];   //reset both arrays arr1 = arr2 = [];   //add a single item in arr2 and arr1 arr2.push( 32 ); arr1.push( 10 );   //print both arrays and you will see same result //OUTPUT: 10, 32 alert( arr1.join() ); alert( arr2.join() );

On line 1 and 2, two arrays are created. Then those arrays are reinitialized with blank array in a single statement on line 5. The problem with this statement is that now both arrays (arr1, arr2) are pointing to same array in the memory. So changes in one will automatically be reflected in the other.

On line 8, integer 32 is added in arr2 and on line 9, integer 10 is added in arr1. To check the output of both arrays, join method is called on each of them on lines 13 and 14. Note that both arrays contain same values.

Don’t Forget Keyword var

In JavaScript you can declare variables with keyword var. But it also allows you to use variables without any declaration. There’s a very critical difference between these two ways of using variables. Consider the following example.

function createVar() { var myVar = 'local'; };   alert( myVar ); //output: undefined

As you can see from the above example when a variable is declared with keyword var, it’s not accessible in the outer scope. Let’s change this example to define a variable without var in function.

function createVar() { myVar = 'local'; };   alert( myVar ); //output: local

Note that a variable defined without keyword var in function is also accessible from the global scope. In other words var makes the variable local. So becareful when using variables in JavaScript. Always declare your variables using keyword var before using them.

Not Using Event Delegation

Attaching event handler is simple in JavaScript. For example following code adds a click handler to anchor tag having id myLink.

document.getElementById('myLink').addEventListener( 'click', function() { //you code goes here... }, false );

Now suppose you want to add a click handler to all the td elements in table. Are you going to write a handler for each td in table?

<table id="myTable"> <tbody> <tr> <td>1, 1</td> <td>1, 2</td> </tr> <tr> <td>2, 1</td> <td>2, 2</td> </tr> </tbody> </table>

Here event delegates help us. In our case we will attach a single click event handler to myTable and within that we will check to see if a td element is clicked or not. In this way we don’t have to write and attach event handlers to every td in table. Such kind of handler is known as event delegate. Here’s the code for it.

document.getElementById( 'myTable' ).addEventListener( 'click', function( e ) { if( e.target && e.target.nodeName == 'TD' ) { console.log( e.target.innerHTML );   //to access id //console.log( e.target.id );   //to access className //console.log( e.target.className ); } }, false );

innerText VS innerHTML

New js developers are often confused between innerHTML and innerText properties. Both innerHTML and innerText are used with element objects. innerHTML gets the html code inside the element and innerText gets the text inside the element.

The dark gray background in Html is actually the output of innerHTML property. Note that the Html tags (in our case <p>) are also included in the output.
Let’s take a look at innerText example.

As you can see from the above example that innerText gets the text inside the element (without html tags).

Adding Nodes in Bulk

It’s common in JavaScript to append list of nodes to some element in DOM. For example you may want to append a list of names to ul received from server using Ajax call. One way of doing this is shown below.

window.onload = function() { //ul element - <ul id="list"></ul> var list = document.getElementById( 'list' );   var item = null;   //suppose this json is returned from ajax call var ajaxResponse = [ { 'name' : 'Haiku' }, { 'name' : 'Linux' }, { 'name' : 'OS X' }, { 'name' : 'Windows' } ];   //add all names in ajaxReponse to documentFragment for( var i in ajaxResponse ) { item = document.createElement( 'li' ); item.appendChild( document.createTextNode( ajaxResponse[ i ].name ) ); list.appendChild( item ); } } //end onload   /* ..:: OUTPUT ::.. <ul id="list"> <li>Haiku</li> <li>Linux</li> <li>OS X</li> <li>Windows</li> </ul> */

The problem with this method is that each time the item is appended to list in "for in" loop, the DOM gets updated immediately. This hurts performance because DOM manipulation is costly process.

“DocumentFragment is light weight version of document and it has no visual representation on the web page.”

The same output can be achieved using DocumentFragment. DocumentFragment is light weight version of document and it has no visual representation on the web page. Following is the example to append list items using DocumentFragment.

window.onload = function() { //create DocumentFragment var documentFragment = document.createDocumentFragment();   var list = document.getElementById( 'list' ); //<ul id="list"></ul> var item = null;   //suppose this json is returned from ajax call var ajaxResponse = [ { 'name' : 'Haiku' }, { 'name' : 'Linux' }, { 'name' : 'OS X' }, { 'name' : 'Windows' } ];   //add all names in ajaxReponse to documentFragment for( var i in ajaxResponse ) { item = document.createElement( 'li' ); item.appendChild( document.createTextNode( ajaxResponse[ i ].name ) ); documentFragment.appendChild( item ); }   //append all items in documentFragment to list list.appendChild( documentFragment ); }

DOM Manipulation using innerHTML

Never use arithmetic assignment operator (+=) with innerHTML to add new markup. Whenever you change innerHTML, DOM updation occurs (Browser redraws the markup). So adding new markup using += operator (specially in a loop) decreases performance.

var container = document.getElementById( 'container' );   for( var i = 1; i <= 10; ++i ) { container.innerHTML += 'Item ' + i + '<br />'; }

Always use a temporary variable to store the markup you want to assign to innerHTML as shown below.

var container = document.getElementById( 'container' )
  , str = '';
 
for( var i = 1; i <= 10; ++i ) {
    str += 'Item ' + i + '<br />';
}
 
container.innerHTML += str;