Wednesday, November 23, 2011

Compiling multiple projects into a single exe file in WPF

A long time ago I wrote a simple application using WPF (I will write about this utility in my next post) that I recently dug up from the lost archives and I wanted to use in my every day life (at work & at home).

I realized that this small application was made up of 3 projects, thus creating one exe file and 2 extra dll files.
Since I want to pack it light, and I truly see no reason to carry around 3 files that are all under 1MB, I looked for a way to compile all of this under one file.

After looking on the internet a little bit, I found a simple solution, which probably isn't the best way to do it but it works good enough for me...

First, in my main project, I created a folder called Assemblies, and put the other compiled dll's into this folder manually. Then, I defined these dlls' Build Action to be 'Embedded Resource' (this is found in the properties window of every file in your project - image attached).
This will cause the dll's to be compiled as resources embedded into the output exe file.

And now that the dll's are in the exe file, we can delete the dll's in our output folder and just run our exe file, right?
Wrong! The CLR will still look for these files in the folder (and also in the GAC) and when it doesn't find them it won't know what to do.

So all we need to do actually, is just tell the compiler where to look when it doesn't find the files in the original location.
This is done by overriding the method 'AssemblyResolve' in our current AppDomain object like this :

AppDomain.CurrentDomain.AssemblyResolve += (sender, args) =>
        String resourceName = "MyProject.Assemblies." + new AssemblyName(args.Name).Name + ".dll";
        using (var stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(resourceName))
            if (stream == null) return;

            byte[] assemblyData = new byte[stream.Length];
            stream.Read(assemblyData, 0, assemblyData.Length);
            return Assembly.Load(assemblyData);

What we did here is just retrieve all the embedded resources and find the specific assembly the CLR was looking for.

Now, after compiling your project, you can delete the other dll files in your output folder and the exe file will work on its own.

While thinking of this solution, I didn't like the idea of having to copy the assemblies after every change into the 'Assemblies' folder I created, and then compiling again... but after thinking about it for a while, I think it's not that bad in my case if I consider the circumstances - I'm talking about a very small solution, only 3 projects, and all i need this packing into one file for is to move it around. I also don't believe I will be working on it that much more, so this means I just need to do this once. If it was a current project at work or even for fun, I wouldn't go with this option, and i would've found a better way around this...

An extra note : While running the application for the first time, it immediately crashed. I opened it in debug mode (which actually meant I needed to put a Thread.Sleep() in the initialization and then attach to process through VS since I wanted to delete the dll files before debugging). I realized that the application was looking for an assembly called XmlSerializers that I never created. I don't know exactly why, but it turns out that this was automatically generated while compiling. No worries though, this can be taken care of. Just go to the project properties > Build > Output > Generate serialization assembly = Off.

Monday, November 7, 2011

Breaking The Build

Today was one of the hardest days at my new job (at Sears Israel) since I started working there...

It all started when I arrived very early at work (around 8:00am) because I wanted to get a lot done, but instead I arrived and immediately found out that one of the acceptance tests I wrote (automated UI testing) was failing and breaking the build on our integration server.
So instead of getting straight to my regular tasks, I started looking into the problem which unfortunately, took a big part of my day. I don't want to bore you with details about why the test was failing since there's nothing technically interesting about it, but I do want to share with you what I learned from it.

We write A LOT of tests! Unit tests, integration tests and acceptance tests. We spend a lot of time writing them and a lot of time thinking how we can improve the framework and make the tests even better in the future. I haven't been familiar to this kind of attitude in the past, but from what I see already at Sears, is that this attitude pays off big time in the long run!
Today, I spent a big part of the day "not getting any work done", and not learning anything new about good design, nor better programming techniques... I spent time digging into my code, until I finally found out that the problem had nothing to do with my code. Even though, I still think this is a good lesson to learn from. During the whole time spent debugging, all I could think about was putting an 'Ignore' attribute above my test, committing, and finally getting back to my regular work, but this would just be cheating and beating the point all together. Doing this would've been taking all the countless hours spent writing these tests in the company and saying they don't matter and just throwing them away. If we don't care enough to maintain these tests like they should be, then we are eventually throwing them away, along with all the time spent on them...

Today, if I start working on a project, even just for myself at home, just something for fun, I can't imagine doing that without writing the proper tests to go along with it. This is becoming an integral part of coding for me...

All in all, I went home today with a good feeling. I know that the tests work, the code is of good quality and I did my part to keep that true now, and in the future. This feeling is rewarding and pays forward to the "hard day" feeling I had while confronting the problem I just wrote about...

Monday, October 24, 2011

The New Environment

I just recently posted about moving on - the decisions I made, why I made them and what I feel about it...

Well, now that only two 'innocent' weeks have past since I started working here, I already have a lot to say about this. Off the bat, the decision was brilliant! The people here are great. Each one of them has many experience, each in his specific field, and they love doing what they do best. They also enjoy helping others and making sure the 'team' does a great job together which is amazing.

I won't even attempt to name all the new things I've learned during this short period working here, but just to name a few -

Agile :
DSM's, Poker Planning, and Retrospective meetings are all great ways to keep the team focused. They don't get in your way, and they always keep you on track with what's going on.
In my previous job, there were times when some people in the team don't know what some of the others are doing. This can cause a lot of code to be rewritten for no reason, people to be spending time on bugs that someone else on the team knows how to fix and poor design since the more people involved in the design the better it will turn out to be.

Productivity :
Everyone here is super productive and it seems like they dedicate time finding ways to be even more productive.
ReSharper is one of the gems in the field!! I never realized how much more coding can be done when you just have the right tool and I don't want to even try to imagine going back to programming without it. (This is said without even knowing half the features this tool has, even just knowing about Ctrl+T & Ctrl+Shift+T are enough!!)

Coding :
The first two weeks here the team leader let me solve bugs on the system, which I think is a brilliant way to learn the code. If the bugs are well chosen, then you will even learn everything there is to know about the system you'll need to work on very soon. While looking at the code, and fixing bugs, I learned a lot about designing good and maintainable code. I'm not gonna say it's perfect, as in every place, but there are so many concepts in design patterns I've learned just from debugging and reading the code.
Just some of the new concepts I've learned here are : IoC - Heavy use in many brilliant ways of the windsor container. Convention over Configuration - Never realized the great power of this concept before, how it effects your code and why you should always keep it in mind when coding. Continuous Integration - This is amazing! Never thought it would be possible to deploy to production so many times a week or even day! Selenium - Great automated way to check your web application across browsers. And the list goes on....

Hopefully I'll be posting more now that I'm learning a lot of new stuff.... :)

Monday, September 19, 2011

A New Direction

I finally decided to move on...
After working for two years at an Israeli credit card company (ICC a.k.a. C.A.L.) as a .net web developer, I think it's time for me to start something new!
Here are some of the thoughts and questions running through my head at the moment :

What did I accomplish in the past 2 years ?
My technical programming skills did improve, but not as much as I would want them too. That's exactly why I'm leaving.
I did gain experience and I feel that I did improve but not to my full potential. During these two years I had to learn a lot on my own, reading blogs on the internet, and trying to incorporate the new technologies at my work place. Most of the people at my workplace have been there for a couple of years prior to me arriving and they aren't keen on letting some new dude change the way they're used to working.
You know what they say - It's really hard to teach an old dog some new tricks... :)

What was I looking for ?
When I started looking for a job, I decided that the most important aspect to me is a place where I will advance technically and learn as much as I can from. As a programmer I believe that half the job (at least) is to always learn new technologies/frameworks/utilities that will help you become a better and more efficient developer. I believe that if the people at your current work place aren't always pushing to learn new technologies then it will be very hard to do it on your own... (If you succeed, tell me how).

Where am I going ?
After only a few interviews, I decided to start working for Sears Israel (SHC). The first thing that got me intrigued about them is that they were the only place that during the technical interviews actually asked me some questions that I didn't have a clue to the answer! During the interviews, from my first impression, it seems like the programmers there really know what they're doing and are fully dedicated to writing excellent code!
In addition to the technical stuff, the product seems interesting, and a very modern idea. It's basically a social shopping site, but with tons of interesting features. I know that the challenges they deal with are interesting - The most interesting to me is how do you create a site with great scalability?...

Some more general and honest thoughts about the new job...
Brutal truth to be said - I'm a little worried I won't live up to the standards at Sears. My new team leader sent me some subjects/frameworks to learn before I arrive so I'll feel a little more comfortable when I arrive. Some of these technologies/frameworks I haven't used much or at all in the past (like IoC & MVC3), and some (like Apache & Tomcat + Java) are totally new ground for me. But this just makes the job 10 times more interesting to me! I just hope I'll be able to learn all the new stuff fast enough so I can keep up with the pace.
But this doesn't make me put my self down, instead it just makes me want to get so much better at what I love doing (programming!). I don't have experience looking for and hiring employees, but I think that one of the most important things you should look for in a new employee is someone that loves what he does and that you know will always be open to learn new stuff from other sources. Of course you want someone that has a certain amount of programming knowledge, but someone who is very experienced but has no motivation will be a bad bet in the long run apposed to someone a little less experienced but fully motivated.
I believe I fit into the fully motivated category. I know for a fact that I love learning new stuff, and that I'm always open to changes, so I think i'm a good bet... :-p

Saturday, August 27, 2011

Unit testing FluentNHibernate...

As I recently posted, I just got back to unit testing...
I thought of a small personal project to start practicing on, and got to work. My project consisted of using Fluent NHibernate, so I wanted to create unit tests to make sure my mappings were good.

I came across an old blog post of Ayende explaining that he created a base class that exports all your mappings into an in-memory sqlite db just for testing.
This concept seemed really good to me, so I tried it myself, but ran into some small problems while trying to configure it for Fluent NHibernate, so I will post the new version to ayende's class that works for FNH :

In case you don't have the SQLite providers yet, you can download them here.

This is the class :
public class InMemoryDatabaseTest : IDisposable
    private static Configuration configuration;
    private static ISessionFactory SessionFactory;
    protected ISession session { get; set; }

    public InMemoryDatabaseTest(Assembly assemblyContainingMapping)
        SessionFactory = Fluently.Configure()
            .Mappings(m => m.FluentMappings
            .ExposeConfiguration(x => configuration = x)

        session = SessionFactory.OpenSession();

        SchemaExport export = new SchemaExport(configuration);
        export.Execute(true, true, false, session.Connection, null);

    public void Dispose()

And then all you have to do to test your mapping would be something like this :
public class UserTests : InMemoryDatabaseTest
    public UserTests() : base(typeof(UserMapping).Assembly)
    { }

    public void UserMapping_CanSaveAndLoadUser()
        object id;

        using (var tx = session.BeginTransaction())
            id = session.Save(new Dal.Entities.User()
                Username = "unittest",
                Password = "unittest1234",
                Email = ""



        using (var tx = session.BeginTransaction())
            var user = session.Get<Dal.Entities.User>(id);

            Assert.AreEqual(user.Username, "unittest");
            Assert.AreEqual(user.Password, "unittest1234");
            Assert.AreEqual(user.Email, "");


It's that easy! :)

Thanks Ayende!

Monday, August 15, 2011

Beginning Unit Testing...

I finally decided to get back into Unit Testing...

I have worked once in the past for a short period of time (only a couple of months) with unit testing, and my experience is good with it. The problem is that where I currently work, my team isn't really into it, and aren't to keen on trying neither.

Since I haven't used it in a while, it feels to me as if I lost my unit testing mojo, and need to learn everything from scratch again.
At first, I though the best way to start is to actually write unit tests for projects I already wrote. This isn't TDD at all, but it's still something, and I feel as if I'm getting the "infrastructure" ready for the rest of the process...

Another thing I just thought about doing today was giving a lecture at work to my fellow team mates on unit testing, hoping that they will see the good side to it, and they'll want to know a little more on the subject!

Sometimes the best way to learn is by teaching! :)

I started building a demo project that I will show as part of a presentation i'm working on to go with my lecture. The project is just a simple calculator.

I am gathering all the points I need to discuss on this lecture, but trying to keep it simple and as convincing as possible to people who don't think it's useful or don't know what it is yet. Seems like quite a challenge, but I'm up for it!

So far this is what I got : (these are the points that are going into my presentation)

Let's say we're building a new class as part of a winform that does some calculation. How do we usually go about testing this ?
We would press f5 (debug) and play around with the UI a bit to see that everything's working...

Why is this bad ?
1. We have to do this again and again every time we change a little piece of code since we can't be sure it still works.
2. If someone else on the team changes our code, we'll need to run the tests again.
3. Someone might change a piece of code, play around with the UI and still not know about special corner-cases we were looking to handle in a specific way.
4. Time consuming!
5. In this case it's a winform and might be easy to test manually, but if we're just building a web service for example, I usually see people building these funny "tester" projects that they can send some sample input and see what happens.

Why does writing Unit Tests make life easier ?
1. By writing unit tests we are writing code that will check our functionality instead of doing it manually.
2. We can run the tests every change we make, and this will be much faster then manually testing.
3. If we write the tests properly and cover all the code we wrote, then someone else can change the code around or add some other functionality with the knowledge he didn't screw our code over!
4. Just by looking at the unit tests we can spot the corner-cases we should look out for.

What do we test and what not to test ?
1. Test all public methods in a class. If the tests are written good enough, then the private methods will be covered within these tests.
2. Make sure you're not writing tests to check the .net framework - this means you don't need to go crazy and start writing tests for each .net method!
3. Tests shouldn't need configuration. You should always be able to run the tests immediately. This means you need to avoid having your tests writing out to log files, db, network streams, etc. Instead, create mocks of these interfaces so they don't actually do this during testing.

Well, I feel like I'm new to this as well, so I'm looking for some feedback on these points I have for my presentation so far...
During the presentation I also want to show the simple demo test project I created, and how to write basic tests for it. I will show common cases when changing code can cause different behavior that might not be spotted at first by manually testing...


P.S - Anyone interested in learning more about unit testing should check out these blogs : Ayende & Roy Osherove

Wednesday, July 27, 2011

Finding log4net hidden exceptions....

Recently I worked on a project that was mainly a couple of Web Services, and included a couple of more C# class libraries (e.g : a Data Access Layer, Common project with general utilities, etc..).

In the web services code, we had a lot of calls to our logging utility, which in this case used log4net. I had previous experience using log4net, so I knew (or thought i knew!) how to set it up quickly. I added what I needed in the web.config file, and thought it was enough.

Once I started testing the web services out, I realized that something was wrong with the log4net configuration. The problem was that it wasn't writing anything to any log file whatsoever. The bigger problem was that we didn't know why!?!...
log4net doesn't throw any exceptions if it doesn't work, and this way it doesn't interfere with your running application if, lets say, the log file it should write to has been deleted or is locked by another application for some reason...

However, log4net will write to a trace file, if you set one up...
This led me to the solution of my problem. All I did, was add a TextWriterTraceListener in my web.config, without even altering any code, and the log4net error was immediately written to my trace file.

In my case, I forgot to tell log4net to use Xml Configuration, but this is irrelevant. The point is that this might help you find out what your error is in the case of misconfiguration with log4net...

To set up a trace file through log4net, just add :


to your web.config file.

Trace listeners are a powerful tool when used wisely :)
You can read more about them here : MSDN - Trace Listeners

Happy Tracing...

Sunday, March 20, 2011

Generating dynamic forms :: part 1

Let me start out by saying, I know there are already a gazillion posts on the subject of generating dynamic forms using I'm not posting this to teach the world something new, yet just to give in on the subject a little bit. This task is just so common that it's worth having a lot of examples out there and let people choose which suits them the best.

Generating dynamic forms can be done in so many different ways, and there is no 'right' way or 'wrong' way. Each way has its specific pros and cons.
I was put up to the task of creating dynamic forms from data in the db, again, this time for a web application at work. I searched the internet for articles on the subject to get ideas from and to get a direction. I saw so many different ways to do this, and got lost in all the information that i just decided to think it through on my own and give it my best shot.

I will post about the solution I came with in parts (since i'm guessing it will be long...).
In the first part, I will talk about making some basic decisions before starting to program.

I'm creating the application with C# on the server side. For the client I'll be using javascript obviously, and leaning heavily on the jQuery framework since I know it the best.
In my DAL (Data Access Layer), I'll be using Fluent NHibernate to work with my DB (also a big fan of FNH).

Describing the forms
My forms are built like most forms - Each control is made up from a label and an input of some sort. The basic inputs are a textbox, a checkbox, a combo. Combo's for example can have multiple values, so they'll need to receive a list of values from somewhere. Each control will also need to implement validations.
I will also want to be able to implement special inputs like a datepicker which has a calendar you can choose from, or an address control which the street combo is linked cascadingly from the city combo.

So, so far, im guessing each control in the form will be described by the properties : Label, Name, Type, ListOfValues (this will be a list), Validations (also a list), CurrentValue.

Creating the forms
In my application, I want the forms to be opened in client-side dialog windows, because the user is supposed to view an available list of forms to fill out, open some of them, and fill their values. In the end, the user can choose to save all the information in the forms.
So, I will be implementing the creation of the forms on the client via javascript. I will render to the html source, all of the forms objects in json format, and when the user chooses to open a specific form, I will create it specifically in a dialog window.
I will then save the values into the json, and using ajax, send the information back to the server.

Form Interactions
Each control will have a 'Validate' method, so i can choose to call it when i want. Obviously, the best time to do this is when the user submits.
Submitting the form and a button for submition can be implemented on my own, with no connection to the form builder. I want my generic form builder to help me in the future in every situation, and i can't predict what submition scenarios i'll need in the future so i'll just implement it on my own everytime.

Submitting the form
Like stated earlier, saving the form values will go directly back into the json object where they came from. I will then send it to the server via ajax, and do the db updating on the server side.

Coming up...
In the next post I will start getting into the nitty gritty.
I will show how I built my db representation of the forms - What my entities look like, what are their properties and how they are built.

Saturday, March 5, 2011

Fluent NHibernate - Working with Database Views

So, it turns out you can work with Views with Fluent NHibernate just as you were to work with tables. All you need to is define your entity with the name of the view, instead of the table name.

example :
public class UserEntity
    public virtual int UserId { get; private set; }
    public virtual String FirstName { get; set; }
    public virtual String LastName { get; set; }
    public virtual int UserStatusId { get; set; }
    public virtual String UserStatus { get; set; }

public class UserEntityMap : ClassMap<UserEntity>
    public UserEntityMap()
        Table("view_Users");  // this is mapped to a view, and not a table

        Id(x => x.UserId);
        Map(x => x.FirstName);
        Map(x => x.LastName);
        Map(x => x.UserStatusId);
        Map(x => x.UserStatus);  // This field is from another table
                                 // it is from a seperate code table that describes the different statuses in the system

An exception is thrown, when trying to update the entity that is mapped to a view. The problem is actually because when working with a view, you cannot execute an update query that updates rows on different tables. It will only work when updating rows on one table in the view.

In order to get around this, we need to tell the mapping that some properties aren't to be updated. This will solve the problem.

example :
public class UserEntityMap : ClassMap<UserEntity>
    public UserEntityMap()
        Table("view_Users");  // this is mapped to a view, and not a table

        Id(x => x.UserId);
        Map(x => x.FirstName);
        Map(x => x.LastName);
        Map(x => x.UserStatusId);
        Map(x => x.UserStatus).Not.Update();

Marking the mapping class with '.Not.Update()' tells FNH to return false on the update property of this field.
Likewise, we can also mark an attribute as '.Not.Insert()' and then the field will only be updatable, or mark a field as '.ReadOnly()' and the field will act as if it has a private set.

Thursday, February 17, 2011

jQuery Templates

I am a big fan of jquery, as it is my favorite javascript framework. It has many great features already, and even more are being developed everyday. It simply makes developing responsive web applications much, much faster.

I am currently working on a large application that displays the user a lot of grids practically on every screen. The data inside the grids, as well as there basic structure can change according to different selections the user makes. It is very important for me to make this web application very responsive and fast, so it was pretty obvious from the start that I'd be using a lot of ajax and depending heavily on the client to do the rendering.

I had a standard ajax call, returning me a json object to work with. I then found myself trying to dynamically build a string that would represent the html markup of a
inside a table, appending it to the table as i iterate over the json properties.
This isn't very difficult to do at first, but will always look very messy, and will be much uglier to maintain...

Luckily, just in time, I came across the jQuery documentation of their new templates feature.
This allows you to design a small template of html, mark where the parameters will be, and bind a json object to that template.
Then, you can practically do whatever you want with it- append it to a table, or just use it as a list of data, and the best part is that the UI is seperated from the 'code', meaning it is very easy to maintain since you can change your template around freely and easily, while never changing the ajax calls nor javascripts.

I'll show some simple examples so you can see what i mean, and to help get you started on your own.

First, you obviously need to include the templates plugin into your html file (can be found here) :
<script language="javascript" type="text/javascript" src="Scripts/jquery-1.4.1.js"></script>
<script language="javascript" type="text/javascript" src="Scripts/jquery.tmpl.js"></script>

The template you want to use, could be inserted into a script tag like this :
<script id="templateStructure" type="text/x-jquery-tmpl">
Notice that I gave the script an id, which we'll need soon, and the type is marked 'text/x-jquery-tmpl'.

The ${} brackets tell the jquery where to place the data of the json object we will bind. The name inside the brackets must correlate with the properties of the binded json object.
This means our json object will be an array of objects (or one object if thats all we have) that all have the properties 'FirstName', 'LastName' and 'Email'.

The template I created represents a row in a table that i will bind to, and the table im going to bind it to, looks like this :
<table border="1" id="templateTable">
        <td><b>First Name</b></td>
        <td><b>Last Name</b></td>
So when I add the rows, the table will be filled with data.

In order to load the template, I use the template() method :
This will load the template we defined in the script tag and call it 'myTemplate'.

Now, all we need to do is give the template a data source, and place it wherever we want. In our case we'll append it to the table so it 'fill' the table's data.

$(document).ready(function() {
    // our data object we will bind
    var myData = [ {FirstName:'Bob', LastName:'Jannovitz', Email:''},
                   {FirstName:'Howard', LastName:'Shennaniganz', Email:''},
                   {FirstName:'Joe', LastName:'Stoozi', Email:''} ];

    // load the template and name it 'myTemplate'

    // bind the data to the template and append to the table
    $.tmpl('myTemplate', myData).appendTo('#templateTable');

The final result will be the table with the data rendered into it.

So in conclusion...
The templates jQuery plugin can be extremely useful in binding data to an html template on the client for fast responsive applications. It also has many more great features like instructions that can cause your template to act different to different data situations.
It is important to note though, that all this is only in beta stage, and is subject to change. I however, already started using it, and so far so good... :)

I might be posting something more advanced about this soon, but until then -
You can read more about it here :

Monday, February 14, 2011

Working with Entities instead of DataTable objects...

I started working on a big new project at work, with a couple of other programmers. This project involves a really big ERD, meaning there are a bunch of entities in the DB, with a lot of relationships between them.

I personally am very fond of working with ORM's, and I am especially familiar with NHibernate which is great in my opinion, and would really work fine in this scenario.
Unfortunately though, some people involved in the project didn't want to work with NHibernate, or any other ORM, with the excuse of "some people aren't familiar with ORM's", "I had bad experiencing working with ORM's in the past", yada, yada, yada...

I'm guessing a lot of you are familiar with this kind of frustration at the work place, with corporate politics and people that aren't keen on learning new technologies.
Instead of getting all frustrated about it this time and trying to fight over a lost cause, I decided to make the best of it...

Obviously, this project, like all the others, is on a very tight schedule.
...So writing up my own ORM, without calling it an "ORM" is out of the question! :-P
I decided to do the least that will help.

Here's my solution :
- I Built the ERD in the db. In this case it's Oracle 11g.
- Then I built a lot of different views so that I will see all the data like the Entities I would've used in an ORM.
- I created a simple DAL, using plain ADO.NET, that has the ability to execute stored procedures, and return DataTable objects (super-straight-forward here).
- I created a class for every entity I will need to work with. Each entities class is built in such a way that all it's properties match all the columns in a certain view that I built in the db.
- I created a small utility that will convert my DataTable's into the entities I built, and then I can work with all the data like i would with objects and not DataTables.

The method that converts a single DataRow into the chosen entity uses reflection (obviously), and looks like this :
public static T ConvertToEntity<T>(this DataRow tableRow) where T : new()
    // Create a new type of the entity I want
    Type t = typeof(T);
    T returnObject = new T();

    foreach (DataColumn col in tableRow.Table.Columns)
        string colName = col.ColumnName;

        // Look for the object's property with the columns name, ignore case
        PropertyInfo pInfo = t.GetProperty(colName.ToLower(),
            BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);

        // did we find the property ?
        if (pInfo != null)
            object val = tableRow[colName];

            // is this a Nullable<> type
            bool IsNullable = (Nullable.GetUnderlyingType(pInfo.PropertyType) != null);
            if (IsNullable)
                if (val is System.DBNull)
                    val = null;
                    // Convert the db type into the T we have in our Nullable<T> type
                    val = Convert.ChangeType(val, Nullable.GetUnderlyingType(pInfo.PropertyType));
                // Convert the db type into the type of the property in our entity
                val = Convert.ChangeType(val, pInfo.PropertyType);
            // Set the value of the property with the value from the db
            pInfo.SetValue(returnObject, val, null);

    // return the entity object with values
    return returnObject;

In order to use this method on a DataTable as well, we just need to iterate on the rows and insert them into a list.
I did it like this :
public static List<T> ConvertToList<T>(this DataTable table) where T : new()
    Type t = typeof(T);

    // Create a list of the entities we want to return
    List<T> returnObject = new List<T>();

    // Iterate through the DataTable's rows
    foreach (DataRow dr in table.Rows)
        // Convert each row into an entity object and add to the list
        T newRow = dr.ConvertToEntity<T>();

    // Return the finished list
    return returnObject;

Both of these are extension methods. A great use of them in my opinion.
You just need to stick these into a static class, and it gives you the ability to invoke this method on any DataTable you like throughout your project and getting back any type of object you like.
DataTable dt = Dal.GetCompanies();
List<Entities.Company> companyList = dt.ConvertToList<Entities.Company>();

Now, when my DAL returns me a DataTable, I can easily convert it to a list, and work with that as if I were with regular objects.
In my case, most of the project is supposed to end up to be a couple of web services, that select the data from the db, do a bunch of manipulations, and return it in a big xml. So using this concept in this specific case helps me out a lot, since after manipulating the data, I just need to serialize it as XML, and send it as a web service response.

If I needed to insert it back to the DB though, It would be pretty easy to create a method to convert entities back to DataTable objects.
Probably something like this :
public static DataTable ConvertToDataTable(this object obj)
    // Retrieve the entities property info of all the properties
    PropertyInfo[] pInfos = obj.GetType().GetProperties();

    // Create the new DataTable
    var table = new DataTable();

    // Iterate on all the entitie's properties
    foreach (PropertyInfo pInfo in pInfos)
        // Create a column in the DataTable for the property
        table.Columns.Add(pInfo.Name, pInfo.GetType());

    // Create a new row of values for this entity
    DataRow row = table.NewRow();
    // Iterate again on all the entitie's properties
    foreach (PropertyInfo pInfo in pInfos)
        // Copy the entitie's property value into the DataRow
        row[pInfo.Name] = pInfo.GetValue(obj, null);

    // Return the finished DataTable
    return table;

Some final thoughts on this...
This obviously isn't the best solution to this case, and obviously isn't something ground-breaking neither. I decided to show this as presenting a simple solution that helps a lot when it comes to trying to deal with shitty (in my opinion, obviously) circumstances.

Hope this helps, at least some... :)

Wednesday, January 26, 2011

Join on tables using Fluent NHibernate

I started using Fluent NHibernate about a year ago as I was experimenting with ORM's in general when a good friend introduced me to the framework.
First of all, I felt that learning Fluent NHibernate in the first place wasn't that easy. I eventually found everything I needed on the internet, but for some reason, it wasn't as easy for me as other frameworks i've dealt with in the past.

Enough said, there were some things that I couldn't find how to do on the internet, like how to join two different tables using Fluent NHibernate mappings. I even spotted some people thirsty for answers...
Check out this question on that I found as I was looking for the answer myself, and eventually ended up coming back to answer the question myself! :)

I'll show this using a simple example.

I have two entities :
public class FormStructure
    public virtual Int32 FormId { get; private set; }
    public virtual Int32 FormType { get; set; }
    public virtual FormField FieldId { get; set; }

public class FormField
    public virtual int FieldId { get; private set; }
    public virtual String FieldName { get; set; }
    public virtual int? FieldType { get; set; }
    public virtual int? DisplayOrder { get; set; }

Now, I want to be able to create a query on the FormStructure entity, and have the results ordered by the matching DisplayOrder field in the FormField entity. I also want the DisplayOrder field to be available to me as a property of the FormStructure entity.

In order to accomplish this, I will need to create a Join between these two tables.
The first step is to add the DisplayOrder field as a property in the FormStructure entity :
public virtual int? DisplayOrder { get; set; }

Then, all I needed to do was use the Join method on my mapping class like this :
public class FormStructureMap : ClassMap<formstructure>
    public FormStructureMap()

        Id(x => x.Id);
        Map(x => x.FormType);
        References(x => x.Schedule).Column("ScheduleId");
        References(x => x.Field).Column("FieldId");
        Map(x => x.IsMandatory).Nullable();

        Join("FormFields", m =>
            m.Map(t => t.DisplayOrder).Nullable();

Now the query will automatically be created as a join behind the scenes, and I will have the DisplayOrder column available for me in every row.

This might remove some of the rows from the result, if they have NULL values in the added column from the join. To avoid this, add 'm.Optional()' inside the Join method.

In order to query the table with the join like i defined, all i need to do is something like this :
return session.CreateCriteria<formstructure>()
              .Add(Expression.Eq("FieldName", fieldName))

That's all for now.
I think i'll be blogging more about Fluent NHinernate in future posts as well, as I have started using it more heavily lately...

Monday, January 17, 2011

Generating email address images to avoid spam on your site

Now a days you can't publish an email address anywhere without receiving a bunch of spam immediately after. Those spam web crawlers just search everysite looking for everything and anything that resembles an email address.
I very often see people use different variations of writing their email like "myname at" or "myname at mydomain dot com".
I don't think this covers it anymore...
The best way, in my opinion, is to create an image of the email address instead of writing it. (That's what facebook does as well..)

I started working on a user based site, and the users' emails will be displayed throughout the site. So I created a class that will dynamically generate email address images for me so my precious users won't be so vulnerable to all the spam out there.

Here it is :

I will probably make some changes before using this on my site :
1. I don't think it's smart to give the file the name of the actual email address. I'll probably generate some unique ID but built from the users name.
2. I haven't decided yet if I want the image to be a link to contact the user. If so, then I must create a unique id for each user, and have the link lead to that page with the unique id so i can identify the user being contacted.
3. I'll probably add a simple caching mechanism to this, hence create a folder to store all the images, and then check if it exists before creating a new one each time.

Enjoy :)