Gary Farr

Feeling Recursion

I recently implemented a recursive function in my code and wanted to write about my experience.  First, let me say this is not the first time I've written a recursive function and hopefully won't be the last.  However, as a developer I jump at the opportunity to write one.  As someone who loves to avoid the conventional for each within another for each statement the idea of a recursive function just gets me all excited inside. 

Definition:

• A function that calls itself repeatedly, satisfying some condition is called a Recursive Function.

Why would a developer use recursion?

A better question to ask would be why a developer would not use recursion?  The classic for loop within a for loop to update the same property for each item in a multi-dimensioned list is just not practical.  The code itself is just not clean. 

Example of recursion:

I had a scenario where I needed to gather a list of parameters for rows linked via a parent-child relationship.  In a nutshell I had a case where a parent row could be linked to several children rows, which also could be linked to several of their own children rows.  This could go on and on.  I also had to identify the selected row in my list as well for future analysis.  Below is a simple code example of recursion. 

private void UpdateGridRowInformation(UltraGridRow row, List<GridRowInformation> list)

{

   bool isActiveRow = ((Summary)row.ListObject).Key == _activeRowKey;

   int parentListIndex = -1;

   if (row.HasParent())

      parentListIndex = row.ParentRow.ListIndex;

   if (row.HasChild(true))

   {

      //if item has a child then store its Row Information and call recursion //on Child

      UpdateGridRowInformation(row.ChildBands[j].Rows, list);

      UpdateGridRowInformationList(parentListIndex, row.ListIndex, row.Band.Key, row.Expanded, isActiveRow, list);

   }

   else if (isActiveRow)

      UpdateGridRowInformationList(parentListIndex, row.ListIndex, row.Band.Key, row.Expanded, true, list);

}

private void UpdateGridRowInformationList(int parentRowIndex, int listIndex, string bandKey, bool expanded, bool active, List<GridRowInformation> list)

{

      GridRowInformation gridRowInformation = new GridRowInformation();

       gridRowInformation.ParentRowIndex = parentRowIndex;

       gridRowInformation.ListIndex = listIndex;

       gridRowInformation.BandKey = bandKey;

       gridRowInformation.Expanded = expanded;

       gridRowInformation.Active = active;

       list.Add(gridRowInformation);

}

This code runs through all parent child relationships and adds particular row elements to a list if that row has its own children.  This also adds the selected row’s elements.

Conclusion:

Recursion is clean, easy, and extremely beneficial in programming.  There are dangers to watch out for though.  Just like for loops there must be a way to exit the function cleanly.  Keep in mind that because the function calls itself again and again a spiral effect is created.  The first time the function is called will not finish until the instance it calls is finished.  That instance does not finish until the instance it calls is finished.  And this cycle continues.  Therefore, if the function continuously calls itself with no calls ever finishing, the application will be stuck running in that part of the code most likely causing the CPU utilization to increase and the application to halt.

In my case, I will eventually get to the last row of the last child, then the function will unwrap and my code will continue.  This is a pretty simple example of recursion however it is a very powerful method used for development. 

Conclusion Part II:

To conclude from a personal standpoint, I am a happy coder as I have written a recursive function in my application <g>!

Chicago PhizzPop Design Challenge! Hands Down Clarity Consulting!!!

The Chicago competition of Microsoft's PhizzPop Design Challenge took place last night at a club called The Underground.  As taken from their website, the PhizzPop Design Challenge pits top interactive, Web, and design agencies against one another to push the limits of technology and creativity in a battle royale.  Six teams compete in six cities with the winners of each city then competing at the South by Southwest Interactive Conference in Austin, TX.  The Chicago competition had Ratchet, Effective UI, Webitects, Clarity Consulting, Tribal DDB, and Magenic as the companies presenting in the design challenge.

The Challenge

Airplanes!  To most, riding an airplane is a miserable experience.  Most hate long terminal lines, taking off and landing of a plane, and of course sitting for X number of hours staring at a PG movie or trying to sleep in those uncomfortable chairs.  Flying, in general, just sucks.  What can be done about this?  Well, Microsoft proposed an in-flight concept based on new technology that could improve a passengers enjoyment.  The technology used to create this concept is Windows Presentation Foundation or WPF.   Each company had three representatives spend two and a half days developing an application using WPF that would somehow make a person's experience on a flight more enjoyable.  The airline the teams are creating this for?  None other then Howard Hughes nemesis Pan Am Airlines.  So this is the challenge!  Last night I was able to see all six companies entries and here are the results.

The Teams

Ratchet

Ratchet was the first company to present.  They actually teamed up with a design company, sorry I can't remember the name.  Its always hard to be the first presenter in a competition as judges tend to remember you the least at the end.  You really have to stand out.  I don't think it helped that it was obvious these developers and designers were Apple 'fan boys' and were not too fond of Microsoft.  I took this by how excited one of them was when he won a Zune in one of the raffles. 

Regardless of their opinions of Microsoft, they used the tools designated for this contest and created a pretty nice application.  The application was easy on the eye, creative, and I believe a really good effort for first time users of these development tools.  They had a simple Kiosk touch screen application on the back of an airplane seat.  A user was able to watch movies (though we didn't actually see a video), chat with other users, and contact people not on the flight using Twitter.  The provided a business case scenario for this, for example if their flight is running late, they can update work.  They also provided an in-flight live map of where the plane's current position is.  In all, it was a good opening presentation and set the bar for what to expect from the other teams.

Effective UI

Effective UI was the second company.  After researching all the teams going into this competition I thought this was the team that had the best chance.  Their company website is very cool, very user interactive, and really demonstrates what I believe is the bar for rich user experiences. 

Compared to Ratchet's presentation, Effective UI's blew it away.  It was a very nice presentation with some interesting additions.  After seeing it I believed it would get some consideration for winning this contest.  The application itself had all the same amenities as Ratchet's with the ability to view movies, chat, plane location, etc.  But besides having some animation, which made the application just more user appealing, they came up with a fantastic idea to have a touch screen at each user's armrest that interacted with their application.  Kind of like a mouse for the user.  I do want to add that there were some really nice zoom features in their app as well.  All in all, very good application that enhanced the user experience immensely. 

Webitects

Webitects was the next company.  I didn't really know what to expect from this company.  After looking at some of their work I thought this was a really good company for this task, but maybe not in the league of Effective UI.  And after their presentation, I still had the same opinion.  They had a web page where users could update their flight information at that particular time.  For example, lets say their flight is being delayed.  A user could go to this website and reschedule a connecting flight for a later time.  However, though this is a nice idea, its something that is pretty normal in today's user experience in flying.  You can get internet access on a plane and do this.  After seeing Effective UI's application, I became all excited with new creative features in a user experience, so though this application was really good, it left an element to be desired.

Clarity Consulting

Clarity Consulting was the fourth company and host for all the developers to work at.  I have to be honest, my review here is going to to be extremely biased because I work for Clarity Consulting.  They are one of the two development companies in this competition out to show that developers can also be good designers. 

To say I was impressed by the presentation wouldn't give enough credit to those guys.   They started with a video of an IPhone application.  They can use this application to book, review the itinerary of their flight, and even view their boarding pass.  They were the first team to present a concept not just for the present user experience but for the future too.  They then demonstrated their Kiosk, which was extremely user friendly, extremely animated, and contained a lot of content.  The one thing, from a user interface perspective, that stood out from the other applications was the look and feel of their buttons.  By having different button sizes, they gave a three dimensional look and feel.  Plus their user interface flow was really impressive.  Moving from screen to screen seemed to be a smooth transition instead of a jump cut (not to steal a movie term).  Definitely was wowed!

Tribal DDB

Tribal DDB, the next company, I thought would be the other big name player based on their website.  Their website was very user rich experienced and its clear this companies is really strong in the design environment.

I really liked their presentation.  It was very clean, had a lot of animation, and there is a lot to be said about colors.  They were the first team to really use colors well.  From a visual friendly point of view, this was the best so far.  That being said the content was similar to all four previous presentations.  They had an obscure movie selection, a very nice seating arrangements viewing GUI, and chat capabilities.   These guys are really good at what they do and this application definitely proved that.

Magenic

Magenic was the final company to present and the other development company in this contest.  I have met and worked with a few of their past and present employees and think very highly of them as developers.  So I was really interested to see what their design team could come up with.

Their presentation was really nice.  It wasn't wowing.  It wasn't animated.  It didn't have features that stood out.  But still, it was really nice.  It was a very clean application that was easy to move around and had similar features to the previous presentation.  One thing I did notice was their team's use of colors, pictures and GUI layout was very good.  I find it strange that the two development companies were just fabulous with the rich user experience part of the presentation.  This was the one area I thought they would be lacking in.

The Judges

Jeremy Alexis an Assistant Professor at IIT's Institute of Design has a tremendous amount of experience in defining next generation products, services, and business models. 

Scott Kinkaid, Vice President of Usability Practices is an expert in defining solutions and integrating the knowledge of traditional lab-based research with online user experiences.

Carlos Segura, one of the most innovative, creative, and talented graphic designers of our time.  His artistry is known throughout the world and most of the presenters were extremely honored to just meet him, let alone have him judge their contest.

The Winners

Carlos was the last to talk about the presenters.  It was interesting that he said one of the most important criteria the judges were looking for was, in a nutshell, innovation.  It was fascinating to know what we could do now with this technology, but where was it headed?  What new creative ideas can arise from the use of this technology.  He followed by saying therefore hands down the winner is Clarity Consulting!  Based on that I think the addition of the IPhone and its usability in the entire flight experience was exactly what the judges were looking for.  Using this technology to be innovative is what design is all about.  All these teams were very technology savvy, artistic, and did a fabulous job on their presentations.  But besides all the cool animation, video, and data in Clarity's presentation they stood out because they were innovative.  They saw what could become rather then what currently is.  On that note, they deserved to win.

Conclusion

I wanted to attend this contest to not only root my co-workers on, but to continue to see what people are doing with this new technology.  I even brought my fiance to give her a visual perspective of the possibilities she always hears me talk about but never sees.  I am lucky as I can feed off of these guys and their expertise.  Not just as developers, but designers and innovators.  So Marlon, Erik, and Kevin congrats to you guys.  You truly deserve it for a job well done.

Chicago IxDA Rich Internet Applications from the eyes of a developer

Last night I attended a monthly Chicago IxDA Rich Internet Applications meeting.  The IxDA website is http://gamma.ixda.org/local.php.  This event was hosted by ARC Worldwide, a marketing services agency.  You can visit their website at http://www.arcww.com.  As a beginner in Rich Internet Application development, my intent was to see how this technology can be utilized in the real world, what are its advantages and disadvantages, and where do people who use this technology every day feel it is headed in the future. 

Demonstrations

In general, I find that when a presenter is demoing their projects it is nice at times to be ‘wowed’, but also nice to feel this was definitely a task I could accomplish.  I had both these feelings while watching these demonstrations.  The first demo, Wilson Sporting Goods website, I was mildly impressed with.  It was pretty, user friendly, and had some interesting animations.  However, I thought the lag time on certain items of the application hindered the overall experience.  This application was built with a mixture of Flash, AJAX, and HTML. 

The next few demos really didn’t catch my attention as they seemed like simple applications.  There was a Facebook application which the developers played around with our Facebook Developer Toolkit, I talked to them a little bit about that afterwards. 

The real ‘wow’ came from the Microsoft rep and his demos of Silverlight, WPF, and an application called Seadragon.  You can check this out at http://labs.live.com/Seadragon.aspx.  I was amazed in every aspect at this application.  Basically, it displays large amounts of data, such as books and magazines, in a readable and viewable format.  The zooming capabilities are simple and cool to use.  Also the amount of data it displays, whether its text or pictures, is very impressive.  Are we seeing the future of literature?  Are books and magazines a thing of the past? 

Discussions

There was an interesting debate on the usage of a Rich Application and when the amazement just surpasses the need.  An example that was brought up often was the comparison of Google Earth to Google Maps.  Google Earth is really cool and everyone has at least used it once, but for practical purposes, most people still use Google Maps to look up directions. 

Another topic was what is the driving force behind Rich Applications?  Web 2.0 was pushed by the developers and designers as they found this easier for wide distribution of an application.  Now that Rich application development is more easily made, with tools like Adobe Flex and Microsoft Silverlight and WPF, how can this impact industry standards to where it’s a viable solution?  What kind of applications do our users want?  Would users still what something that is easy as opposed to something that is visually stimulating yet harder to work with on an everyday basis?  There wasn’t a clear answer to this, but one route discussed was marketing research.  Marketing research for application development is more important now than ever. 

Conclusion

As someone who is really trying to jump on the design bandwagon from a developer background, this meeting really helped me relate this architecture I still deem ‘fun programming’ with core client application development philosophies that I deal with on a regular basis.  I believe the future will consist of a mixture of application design philosophies.  I think the conventional client who wants something simple and stupid but does the job will always be there.  I do also believe more clients will go the route of a rich application as they’d feel this would better their business scenario.  However, that being said with the advancement of technology the way it is, something simple and stupid of the future may be something that’s hard and complex now.  

I am looking forward in having fun with these tools, developing games, websites, etc.  I am also looking forward to writing my first client-based application with them.  The future looks bright for rich application development.

Unable to copy file "obj\Debug\xyz.dll" to "bin\Debug\xyz.dll".

Unable to copy file "obj\Debug\xyz.dll" to "bin\Debug\xyz.dll". The process
cannot access the file 'bin\Debug\xyz.dll' because it is being used by
another process.

I have been getting this error on the project I am working on for quite some time now.  It is an annoying error as the only solution before was to restart the IDE which in my case was a headache as it would take 10 minutes to reload being such a big project.   In doing some research, I discovered that the library that was locking up was doing so because of the way it was being referenced in regards to its project and other project.  It seems if you have a library that is referenced by a library in another project and that 2^nd project library is referenced in a 3^rd project library, then reference the third project library in the 1^st project and then debug through the system, i.e. step through some code, stop the program, re-compile, and this problem will occur.

Alternative attempts to solve this issue:

I first tried to resolve this issue by unlocking to dll from whatever process it was attached to.  I used Unlocker 1.85.  It is a nice tool that displays what processes are currently attached to a library.  It enables you to unlock those processes or kill them.  You can download this tool at http://ccollomb.free.fr/unlocker/.  I have used this tool in the past for similar issues.  However, after I unlocked my particular dll in question and re-compile my code, I still got that error. 

Re-start the IDE.  Obviously this solution is not acceptable, as I stated before.

Final solution:

VS basically locks the file and you cannot use third party resources to unlock it.  Therefore, just use VS!  In the Properties of a project in your IDE you have Buld Events.  Basically, you can write scripts during pre and post builds of a project.  I added these two lines in the pre-build event command line, which basically unlocks the dll within Visual Studio.

Faking alternative controls within a DataGridView control in Win Forms 2.0

One of the limitations of the DataGridView Control within WinForms is that you can only select a few controls to place in the Grid View.  In my case I wanted to add a DateTimePicker Control within a row of the DataGridView.  I searched for example on how to do this.  Microsoft has an example of how to host controls in windows forms DataGridView cells at http://msdn2.microsoft.com/en-us/netframework/7tas5c80.aspx but I really didn’t like the fact that you had to create a column class specifically for that control.  It seemed a tremendous amount of excess code to write for a specific task.  I found a simpler way to in a sense, fake this process.  I simply created a DateTimePicker Control on the form.  I initially set the Visible property to false.  Then, upon a cell click on the DataGridView, I place the DateTimePicker control within that Cell’s limits, i.e. top, left, height, width.  The user then selects a date and as the leave the DateTimePicker control I post that result back to the particular cell.  The code below describes this process.

private void frmCategory_Load(object sender, EventArgs e)

{

this.productCategoryTableAdapter.Fill(this.dsAdventerWorks.ProductCategory);

                // Add the event handlers.

                 dgCategory.CellClick +=new DataGridViewCellEventHandler(dgCategory_CellClick);

                }

protected void dgCategory_CellClick(object sender, DataGridViewCellEventArgs e)

{

//set Date Picker to false when initially click on cell

                if (dtPicker.Visible)

                    dtPicker.Visible = false;

                if (e.ColumnIndex == 2)

                {

                    //set date picker for category datagrid

                    dtPicker.Size = dgCategory.CurrentCell.Size;

                    dtPicker.Top = dgCategory.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, true).Top;

                    dtPicker.Left = dgCategory.GetCellDisplayRectangle(e.ColumnIndex, e.RowIndex, true).Left;

                    if (!(object.Equals(Convert.ToString(dgCategory.CurrentCell.Value), "")))

                        dtPicker.Value = Convert.ToDateTime(dgCategory.CurrentCell.Value);

                    dtPicker.Visible = true;

                }

}

private void dtPicker_ValueChanged(object sender, EventArgs e)

{

                 dgCategory.CurrentCell.Value = dtPicker.Value;

                 dtPicker.Visible = false;

}

                To add, I used this same methodology for a master-detail relationship between two DataGridViews.  I figured that if this can be done for any control, why not build this relation.  The only two differences are I added a handler for Leaving the second DataGridView and I put the second DataGridView along with a bound Navigator within a GroupBox control.  I did this because I wanted particular add/delete/update functionality within the second DataGridView.