Visual Studio 2008 & .Net 3.5 Released

Microsoft released the newer version of Visual Studio(previously Orcas) and .Net 3.5. The VS looks cool; it has a lot of new features like intellisense for JavaScript, new CSS editor, Multi-targeting for previous frameworks etc. There is a trial version(90 days) available on Microsoft's website. Give it a shot.

Trial version:
http://msdn2.microsoft.com/en-us/vstudio/products/aa700831.aspx

some more info on Scottgu's blog:
http://weblogs.asp.net/scottgu/archive/2007/11/19/visual-studio-2008-and-net-3-5-released.aspx

Happy Coding,

Madhu

Debugging Classic ASP in Visual Studio 2005

I couldn’t find a lot of documentation on how to debug the classic ASP pages in VS 2005 running on Windows XP and IIS 5.0. So I tried few stuff and finally figured it out. Here are the steps:

• Go to Control Panel>Administrative Tools>Computer Management. Add IWAM_ComputerName account to the Debugger Users group.
• Create a Web Application Project in VS 2005 and add .asp files.
• Create a virtual directory in IIS for the web application project you created.
• On the properties tab of the virtual directory in IIS do the following:
• Click Configuration button.
• On the Mappings tab, select .asp and click Edit
• Add the DEBUG verb and click OK.
• Go to Debugging tab.
• Enable the ASP debugging and Client Side Debugging, Save the changes.
• Load the web application project and set the breakpoint in the ASP.
• In VS 2005, go to Debug > Attach to Process.
• Select the DLLHost process that runs under the IWAM_ComputerName account.
• Load the .asp file in the browser and break point will bind now.

Happy Coding,

Madhu

Human Element in Software Development

I was listening to the latest dotnetrocks show(#232) and I must admit, I am very impressed by the ideas about the human factor involved in software development. The ideas like "I am not my code" and "code reviewers are not compilers" are very true and must be followed by all developers. Jeff Atwood, who was the guest of the show has a great blog(www.codinghorror.com), which is concentrated on these topics. I added it to my favorite list and you should do so too.

Jeff was saying all developers need a Bill of Rights which indicates the fundamental rights and needs of a developer. I think it’s very true that we need to have those fundamental rights in order to be an effective software engineer. You can read that blog post here. If you haven’t subscribed to the dotnetrocks show, I highly recommend you to start listening to the show. Carl & Richard, the hosts of the show, are great and you can learn a lot about the new technologies and all the developer events happening near you.

Visual Studio "Orcas"

Microsoft recently shipped the March CTP of Visual Studio and .NET Framework "Orcas" release. It has some new language features in both C# and VB.Net like Automatic Properties, Object Intializers, Collection Initializers etc. It also includes LINQ, Microsoft® Expression® designer support for WPF(I think) and more. Check out Scott Guthrie's blog for more on the new features.

Click hete to download March CTP of Orcas.

Happy Coding,
Madhu

Phone Directory using Trie in C#

Trie is an ordered tree data structure that uses strings as keys. Unlike Binary Trees, Tries do not store keys associated with the node. The key is actually determined based on the position of the node on the tree. Any descendants of a node shares the common prefix of the key string associated with that node. Hence trie is also called as Prefix Tree. The word “trie” comes from Retrieval, and it is pronounced as “try”. To read more about Trie click here.

Since this data structure is a prefix tree, trie is commonly used in Dictionaries, Phone Directories and matching algorithms. Trie is best suited for phone directory (any matching application for that matter!) because it is very efficient in matching strings.

So I have decided to implement Trie myself in C#. I have created three classes:

Node: Represents a single tree node;
NodeCollection: Represents the children of a node;
Trie: Trie implementation to insert and search nodes.

Node: Node represents a basic tree node. Node implements both Depth First and Breadth First algorithms to search its children. It also contains its Parent node and Children nodes. Node has a key and a Value; Key contains the single character and value has the actual data of the node. The key of the node is determined by suffixing the single key character to its parent’s key. Node has a special property called IsTerminal and it is set to true if the key or a value represents a complete string. See the picture below:

NodeCollection: This class is a simple collection class which implements the IEnumerable interface for iteration operations. This class contains an internal List class of type Node. NodeCollection implements the standard list methods such as Add ( ),Contains ( ), Remove ( ) etc.

Trie: This class implements the Trie algorithms such as Insert and Find methods. Here is the InsertNode method:

//Inserts Names into the Trie data structure
public static Node InsertNode(string name, Node root)
{
//Is name null?
if (string.IsNullOrEmpty(name))
throw new ArgumentNullException("Null Key");

//set the index, start inserting characters
int index = 1;
//key
string key;
//start with the root node
Node currentNode = root;
//loop for all charecters in the name
while (index <= name.Length) { //get the key character
key = name[index - 1].ToString();
//does the node with same key already exist?
Node resultNode = currentNode.Children.GetNodeByKey(key);
//No, this is a new key
if (resultNode == null)
{
//Add a node
Node newNode = new Node(key, name.Substring(0, index));
//If reached the last charaecter, this is a valid full name
if (index == name.Length)
newNode.IsTerminal = true;
//add the node to currentNode(i.e. Root
// node for the first time)
currentNode.Children.Add(newNode);
//set as the current node
currentNode = newNode;
}
else
{
//node already exist, set as the current node
//and move to the next character in the name
;currentNode = resultNode;
}
//move to the next character in the name
index++;
}
//all done, return root node
return root;
}

The InsertNode method inserts the string as one character at a time. It starts with the first character; if the first character doesn’t already exist in the root node it adds a new node with the that character and returns the new node. Otherwise it returns the node which has that character to add the remaining characters. It loops until it adds the entire string to the root node. Once it reaches the last character, it marks that last node as a terminal node since the node represents a complete string in the tree hierarchy.

The Find methods is implemeted by Depth First search algorithm. The tree is searched until the complete string is found. Below is the code.

//Find a node given the key ex. "Jo"
public static bool Find(Node node, string key)
{
//Is key empty
if (string.IsNullOrEmpty(key))
return true;//terminal Node
//get the first character
string first = key.Substring(0, 1);
//get the tail: key - first character
string tail = key.Substring(1);
Node curNode = node.Children.GetNodeByKey(first);
//loop until you locate the key i.e. "Jo"
if (curNode != null)
{
return Find(curNode, tail);
}
else
{
//not found, return false
return false;
}
}

I‘ve attached the entire source code below. The source code contains the Trie class library and a console application to test the Trie library. The console application loads a set of names (stored in names.txt in debug folder) in to the tree and provides options to run Depth First & Breadth First algorithms. The application also provides options for Directory Look-Up and Find functionalities.

The class library can be further used to develop a web based phone directory. The data can also be stored on the client (if it is too small!) and the Trie can be implemented in JavaScript.
Source Code: <trie.zip>

Happy Coding,
Madhu

LINQ

Microsoft is going to release a new data retrieval technology called LINQ(Language Integrated Querying). You will be able to write queries in C# and VB as you write any other code. The data is retrieved from the database, converted to objects(like a typical O/R mapper) and queried from C# code.

Here is the sample:

//Created by the designer
DataContext db = new DataContext();

//Querying Products table in Northwind database
var query = from p in db.Products
select p;

//Iterating all the rows
foreach(Product pr in query)
{
Console.WriteLine(pr.ProductName);
}

You can create the LINQ objects using the designer and generate the required classes.(Notice the DataContext and Product classes in the above sample. This class will be generated when you drag and drop the tables from the server explorer into the designer.)

You can download the May 2006 Community Tech preview version of LINQ from here. Also the new "Orcas" March CTP will have the built in support for LINQ .