Muney: Financial Management for Students

Over the past year, I have spent quite a long time on my dissertation. I’m pretty proud of it and I have had quite a few positive comments from various lecturers (I’ve even been asked to write a paper on it for a journal). I’ve decided to write a few articles about my work, hopefully it will hope someone out. If your interested in it, my final report can be found here.

My project was a personal financial management application for students (the actual title was FAST: Financial Analysis for STudents although my final application was called Muney). Essentially I was having problems with my finances a while ago, being the good programmer that I am, I had a look at what software was available. To be honest, from a students perspective, Microsoft Money & Quicken are pretty terrible. Users are required to have a significant amount of financial knowledge to use them effectively. In their defense, these app’s aren’t really aimed at the student demographic.

This was obviously a known problem since I found a few web applications such as wesabe & buxfer, which were developed to solve just this problem. Although these applications are much more student friendly they were really basic, not offering solutions for tasks students are commonly pretty poor at performing (e.g. bill management, budgeting)

So based on this, I decided to develop a financial application which automates important monetary tasks and does so in a way which is easy for a student, with no prior financial knowledge, to understand and use. The application was written using C# & Castle Project’s Monorail framework a screen shot is shown below

The application had a variety of features including

• Bulk importing financial information via an OFX parser (currently open sourcing the parser I had to write to achieve this)
• Automatically renaming and categorizng transactions
• Bill managment (including automatically discovering new bills and recognizing transactions as payments for bills via clustering techniques)
• Automatic budgeting (including time series forecasting to predict a users expenditure)

Since i covered quite a few topics devloping these features, i’m going to split this blog into a series of articles. The application can be split up into three tasks, organizing, managing and planning a users finances:

Here are the articles discussing these tasks

• Organization
• Managment (coming soon…)
  
• Planning (coming soon…)

Filed under: .net, c#, castleproject, dissertation, monorail, muney, ofx , buxfer, dissertation, financial management, microsoft money, muney, personal finance, quicken, wesabe

Monorail: Get client’s browser

For future reference, to get the clients browser:

    $Context.UnderlyingContext.Request.Browser.Browser

This is infact accessing the HttpRequest.Browser property so you can then get all the usual info like browser version:

    $Context.UnderlyingContext.Request.Browser.MajorVersion

Hope this helps someone!

Filed under: .net, castleproject, monorail, nvelocity , monorail client browser castleproject web

Visual Studio syntax highlighting for Monorail views

I was just having a look through the options in visual studio 2008 and noticed a new section for selecting the default editor for non-standard files, such as monorail views (.vm). Up to now i’ve either had to make do with the basic text editor or mess around with the registry, neither of which is that much fun. The dialog is in options -> text editor -> file extension you can then choose what editor you want to associate with each file extension. Hope this is helpful to someone!

Filed under: .net, castleproject, monorail, nvelocity, visual studio, visual studio 2008 , visual studio 2008 .net monorail views .vm castleprojec

Get the currency symbol for the ISO 4217 Currency Code (C#)

Had a bit of a problem today. After importing a bunch of transactions I needed to display the corresponding currency symbol. The problem was when you import OFX transactions, the currency is in the ISO 4217 three letter format. Basically the little bit of LINQ below will search through all the culture infos until it finds one with the correct ISO Currency symbol. Its little things like this that make me love linq!

RegionInfo regionInfo = (from c in CultureInfo.GetCultures(CultureTypes.InstalledWin32Cultures)
let r = new RegionInfo(c.LCID)
where r.ISOCurrencySymbol == "GBP"
select r).First();

Hope this is helpful to someone!

Filed under: .net, c#, linq, ofx , linq c# money currency ofx

Problems with the Linq2Sql

I have just been reading Scott Guthrie’s post on the new ASP.Net MVC framework. Firstly, for the most part I am really amazed with what Microsoft have come up with and I am really looking forward to having a play with it. I am worried though about the methods Scott uses for creating models for data access. In the examples he creates a Linq2Sql model for data access and then use the the database context class to encapsulate all the business logic. Anyone see any problems with this? Say you have a User table in the database, Linq2Sql will create a user object which you can perform all the basic CRUD operations. Say you want to add a method to check if a given user has valid username & password (basic business logic), which of these would you think is logical?



DataBaseContext db = new DataBaseContext();
db.IsUserValid(username, password);

or

User.IsValid(username, password);

IMHO the second is far better since firstly when writing code you don’t need to be aware of other objects (i.e. database context) to be access the business logic of that object. Also having all the business logic encapsulated in the actual object enforces code separation so it is easier to maintain since there will only ever be one file which contains all the code relating to the object. Also

So what should you do instead of encapsulating the business logic in the context? Well there are 2 methods which would allow you to encapsulate all your business logic, the first being using partial classes. Using the User example again, say Linq2Sql has created a User object, you would add another file in the Model directory and create a partial class which you can then include all business logic, as shown below:


partial class User
{


public static bool IsValidLogin(string userName, string password)
{

//Some business logic
return true;

}

}


This method will allow separation of code and you don’t need any knowledge of extra classes to use it. Unfortunately this method is soooo .Net 2.0, so for everyone who is needing an excuse to use the new extension methods, here it is:


public static class UserBusinessLogic
{


public static bool IsValidLogin(this User user, string userName, string password)
{

//Some business logic

return true;

}

}

Both methods work fine and will enforce code separation. Its a shame that decided on having a single .dbml file for the models and Context file for the business logic. I would have thought having an individual class for each table in the db (with a partial class containing all auto generated code) would be more logical and scalable.

There are fundamental flaws with this like how do you apply rules to properties (e.g. ensuring that a password is > 7 characters)? Currently this sort of business logic is enforced at the database end which is a bit crap since I thought the whole point of Linq2Sql or any ORM was so the developer doesn’t have to deal with the database!

While I am critical of Linq2Sql, it is still early days and I’m sure as time passes they will rectify the problems highlighted here. Until then, I hope the methods shown here will help you write maintainable code!

Filed under: .net, c#, linq , c# linq asp.net mvc

C# PostCode GeoCoding

Part of my project needs me to get the coordinates for a given post code. I found FreeThePost.org which allow you to perform geocoding querys pretty easily by doing something like http://www.freethepostcode.org/geocode?postcode=rg20eu. Decided to whip up a quick C# object to do it. Its all pretty simple, do something like:

PostCodeGeoEncoder encoder = new PostCodeGeoEncoder( postCode );
Coordinates coords = encoder.GetLocation();

The assembly for it is here, i hope this saves someone a couple of minutes of hassle!

Filed under: .net, c#, geocoding, postcode