Programing Fun

With this post I want to start a series of "Did you know?" regarding programing related topics and db4o features / usage patterns that may not be well known.

As the first one, take a look in the following code:
 

class Address
{
  public Address(string streetName)
  {
     StreetName = streetName;
  }

  public string StreetName { get; set; }

  public override string ToString()
  {
     return "Address: " + StreetName;
  }
}

class Person
{
   public Person(string name, Address address)
   {
       Name = name;
      _address = address;
   }

   public Address Address
   {
      get { return _address; }
      set { _address = value; }
   }

   public string Name { get; set;}

   public override string ToString()
   {
      return "Person: " + Name;
   }
   private Address _address;
}

using (var db = Db4oEmbedded.OpenFile(databaseFileName))
{
   db.Store(new Person("Adriano", new Address("You know where I live")));
   db.Store(new Person("Sulivan", new Address("Monstropolis")));
   db.Store(new Person("Mike", new Address("Who cares?")));
   db.Store(new Address("Foo address"));

   IQuery q =  db.Query();
   q.Constrain(typeof(Person));
   IQuery descendantQuery = q.Descend("_address");
   
   foreach(var result in descendantQuery.Execute())
   {
      Console.WriteLine(result);
   }
}

In this post I presented the following code.

using Db4objects.Db4o;
using Db4objects.Db4o.Linq;
using System.Linq;

class Item
{
public string Name { get; set; }
public Item Father { get; set ; }
}

public class Test
{
 private const string DatabaseFile = "wwwtc1.odb";
 private static void Main()
 {
     Item item1 = new Item { Name = "Adriano" };
     using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
     {
         db.Store(item1);
     }

     using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
     {
         Item item2 = new Item {Name = "Carol",  Father = item1 };
         db.Store(item2);
     }
 }
}

using Db4objects.Db4o;
using Db4objects.Db4o.Linq;
using System.Linq;

class Item
{
  public string Name { get; set; }
  public Item Father { get; set ; }
}

public class Test
{
 private const string DatabaseFile = "wwwtc1.odb";
 private static void Main()
 {
     Item item1 = new Item { Name = "Adriano" };
     using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
     {
         db.Store(item1);
     }

     using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
     {
         item1 = (from Person p in db where p.Name == "Adriano").Single();
         Item item2 = new Item {Name = "Carol",  Father = item1 };
         db.Store(item2);
     }
 }
}

using Db4objects.Db4o;
using Db4objects.Db4o.Linq;
using System.Linq;

class Item
{
  public string Name { get; set; }
  public Item Father { get; set ; }
}

public class Test
{
  private const string DatabaseFile = "wwwtc1.odb";
  private static void Main()
  {
     Item item1 = new Item { Name = "Adriano" };
     using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
     {
         db.Store(item1);
         Item item2 = new Item {Name = "Carol",  Father = item1 };
         db.Store(item2);
     }
  }
}

Since I joined db4o I'm actively following our forums and trying to help developers to get their questions / issues answered.

Starting with this post I want to present the most recurring topics (don't know exactly how many) in the format of "What's wrong with this code".

But before we start you may be wondering where are the other parts (since this is titled as Part XI, where are parts from I to X). Well, they do exists in the portuguese posts (titled as "O que esta errado com este código (Parte ?)") so I decided to continue with the numbering schema ;)

Ok, for this first one, take a look in the following code:

using Db4objects.Db4o;
using Db4objects.Db4o.Linq;
using System.Linq;

class Item 
{
 public string Name { get; set; }
 public Item Father { get; set ; }
}

public class Test
{
    private const string DatabaseFile = "wwwtc1.odb";
    private static void Main()
    {
        Item item1 = new Item { Name = "Adriano" };
        using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
        {
           db.Store(item1);
        }
  
        using (var db = Db4oEmbedded.OpenFile(DatabaseFile))
        {
          Item item2 = new Item {Name = "Carol",  Father = item1 };
          db.Store(item2);
        }  
    }
}

Hi.

Next week I'll attend the second international conference on object databases in Zürich. Woow!

I am sure it will be really amazing moments; I'll have the chance to meet db4o fellows face to face again, to attend to interesting talks, to talk to db4o community members and db4o enthusiasts! Since most db4o team members will meet at Zurich we're taking the chance to discuss db4o directions also. 

Of course, visiting another country (even though being a work trip) and getting in touch with a different culture will be really a great experience. 

My friends knows how much I like chocolates, so I am sure I am going to get some extra weight :)


The not so nice part is that I'll have a 14 hours flight from Brazil to Switzerland and I must admit that I am a bit anxious with the latest flight news (the interesting thing is that I am almost sure I'll have some nice live pair programing session with my good friend Rodrigo while we wait for our flight).


The worst part is to be far from my wife / daughter (I'll miss my daughter's school presentation).


For those that I'll meet at Zurich, see you soon. For everyone else, see you in this blog :)


Best

Adriano

Hi!

Some time ago I started developing a .Net application that requires a control to display hexadecimal values; considering that I could not find a suitable one (and also, that I do suffer for the NIH syndrome) I decided to write one myself.

After some time developing the application I lost interest (since I moved jobs and the main goal of the application was to make my previous job easier) and now it is kind of abandoned but I think that the hexadecimal control may be handy for some developers.

Here is a list of this control's main features:

• Find
  
• Print / Print Preview
  
• Ranges: It's possible to specify that some byte ranges should be displayed with a specific color for instance
• Selection
  
• Cut/Past

In my last post I was talking about some issues I found while trying to automate the process of launching  a web browser, navigating to a specific page and grabbing some results.

I do have a bunch of stickers with sayings: "Works on My Machine (tm)" but this time I could not even use one of them since even in my machine it refused to work :(. So, the goal of this post is to explain the reasons I got so much pain...

Since an image speak for 1000 words, here it is:

Yesterday was a frustrating day. By the morning I started to work (pairing with a really smart friend) on an apparently simple task: to automate the process of starting an internet explorer (ie) instance, navigate to a specific page stored on the local machine, wait for some processing to finish (notified by the page) and grab the results. Having some years of experience with Microsoft technologies, mainly developing COM components, and aimed with (lack of) humbleness I started to write a jscript script to drive IE through automation, after all how hard could that that be? Indeed, the first part was really easy:

var browser = new ActiveXObject("InternetExplorer.Application");
browser.Visible = true;
browser.Navigate("http://programing-fun.blogspot.com");

var browser = new ActiveXObject("InternetExplorer.Application");
browser.Visible = true;
browser.Navigate("http://programing-fun.blogspot.com");
while (browser.Busy) {
WScript.Sleep(10);
}
var element = browser.Document.getElementById("some-id");