Yesterday I was working on a user control and I came across a situation where I wanted to notify the parent page when ever the button in the user control get clicks.

This situation calls for a requirement of having a custom event associated with the user control I can then use in the host page, which encapsulates the user control.

Here is the core source code to required to achieve this functionality:

CustomUserControl.ascx.cs

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;

public partial class CustomUserControl : System.Web.UI.UserControl
{
public event EventHandler SubmitClick;

protected void btnSubmit_Click(object sender, EventArgs e)
{
this.OnSubmitClick(e);
}

protected void OnSubmitClick(EventArgs e)
{
if (SubmitClick != null)
{
SubmitClick(this, e);
}
}
}

Because I needed the event to be executed when ever the submit button get executed, there for I invoked the method at the Submit button click. You can change it according to your requirement.

HostWebPage.aspx.cs

using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data; 

public partial class HostWebPage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
userCustomControl.SubmitClick += new EventHandler(userCustomControl_SubmitClick);
}

void userCustomControl_SubmitClick(object sender, EventArgs e)
{
//DO ANY WORK
}
}

I tried to make this example as simple as possible. Let me know if this helped. Any suggestion or queries are welcome.

Happy Reading

Waqas Ahmed

I came across this toolkit written by Sike Mulliven. And he really did this job perfectly.

In the toolkit, you will find four different controls along with designer and another control inspired from Rick Strahl’s article on the jQueryCalender.

To use the controls all you have to do is just add CSS file references to your page and drag & drop the controls from the ToolBox. Some Screen captures attached for your reference.

jQuery Controls

jQuery TabView

jQuery Dialog

jQuery Slider

jQuery Accordion

You can download these control from the following location

http://cid-cce8a29919c8f422.skydrive.live.com/self.aspx/Public/jQuery/Mullivan.Web.zip

The solution contains the source code for the controls and the test project for it.

I hope these jQuery controls will really add a spice in your UI development for ASP.NET Application. Thanks to Sike Mullivan.

Let me know about your comments and how helpful it can be for you.

Waqas Ahmed

The poll is at the following URL

http://blogs.techrepublic.com.com/hiner/?p=1894&tag=nl.e101

This poll is create by Jason Hiner of TechRepublic and he is a editor in chief.

It will open on Saturday, July 4, 2009 and then the poll will close promptly on July 11, 2009 at 11:59 PM Eastern (8:59 PM Pacific).

Do give your feedback about your potential candidate for this run up and why?

Waqas Ahmed

Hope this will be helpful. Following is the server application code.

using System;
using System.Text;
using System.Net;
using System.Net.Sockets;

class SocketServer
{
  public static void Main()
  {
    StreamWriter streamWriter;
    StreamReader streamReader;
    NetworkStream networkStream;
    TcpListener tcpListener = new TcpListener(3333);
    tcpListener.Start();
    Console.WriteLine("Server Started. Waiting for Client Connection at port 3333");
    Socket serverSocket = tcpListener.AcceptSocket();
    try
    {
        if (serverSocket.Connected)
        {
            while (true)
            {
                Console.WriteLine("Client Connected at port 3333");
                networkStream = new NetworkStream(serverSocket);
                streamWriter = new StreamWriter(networkStream);
                streamReader = new StreamReader(networkStream);
                Console.WriteLine(streamReader.ReadLine());

            }
        }
        if (serverSocket.Connected)
            serverSocket.Close();
        Console.Read();
    }
    catch (SocketException ex)
    {
        Console.WriteLine(ex);
    }
  }
}

When the above code is executed, it will try to listen on port 3333 and will wait for an incoming connection from a client application. Upon start, server application will display a message “Server Started. Waiting for Client Connection at port 3333”. As soon as the server application recives the connection from client application, it show the message “Client Connected at port 3333”.

Now let’s see how our client application code looks like. Our client application will try to connect at port 3333. Following is the Client Application Code:

using System;
using System.Text;
using System.Net;
using System.Net.Sockets;

class SocketClient
{
  static void Main(string[]args)
  {
    TcpClient tcpClient;
    NetworkStream networkStream;
    StreamReader streamReader;
    StreamWriter streamWriter;
    try
    {
        tcpClient = new TcpClient("localhost", 3333);
        networkStream = tcpClient.GetStream();
        streamReader = new StreamReader(networkStream);
        streamWriter = new StreamWriter(networkStream);
        streamWriter.WriteLine("Client connected at port 3333");
        streamWriter.Flush();
    }
    catch (SocketException ex)
    {
        Console.WriteLine(ex);
    }
    Console.Read();
  }
}

When the above client application code will execute, it will look for an opened connection from a server application at port 3333. As soon as it finds the connection, it will establish the connection with it and will send a message “Client connected at port 3333″. This test message will be displayed on server application console.

A Port is an integer that identifies a process running over a network for the purpose of providing a service. A socket is the end point of a two way communication between two processes running over a network. Microsoft .NET provides excellent support for writing programs that leverage the power of Sockets to implement programs that can run over a network to communicate and share data and information. 

In this entry we tried look at how we can work with Sockets using Microsoft .NET and how we can implement a simple client-server program that can communicate over a network. 

Your comments and suggestions are welcome.

Happy reading!

Waqas Ahmed

Well LINQ to SQL is more than just a LINQ implementation for relational databases; it includes a very easy to use graphical object/relational mapping tool. This tool generates an entity class for each table you select from the SQL Server database to which the project connects. The tool also generates an association that relates to each foreign key constraint. Associations eliminate the need to specify joins in LINQ queries that include projections of fields from related tables. The ability to navigate associations is an important feature of LINQ implementations and the Entity Framework.

The advantage of moving from the relational model of tables, rows, and keys to the entity model of entity classes, entity instances, and associations is that entities usually do represent business objects, such as customers, partners, vendors, employees, products, and services. An entity model enables developers to design real world objects with custom properties, associations, and behaviors suited to the organization’s business processes.

LINQ to SQL is intended for 1:1 mapping of tables:entities, although it does have limited support for entity inheritance of the Table per Hierarchy (TPH) type based on discriminator columns. Read only entities can be based on views or stored procedures. The Entity Framework’s Entity Data Model supports joining multiple tables to create a single updatable entity, as well as several types of entity inheritance.

This entry covers a brief overview about LINQ to SQL extension or you can say a LINQ to SQL in a nutshell. I will try to give some examples about the auto generated classes for entities which entity framework create, in some later post.

Till than, Happy Reading.

Waqas Ahmed

The available alternatives for AJAX behavior in your application belong to open source community. Some of the open source frameworks for AJAX are

• Prototype
• Yahoo User Interface Library
• jQuery

My personal favorite is jQuery. There are many reasons for that. One very important one is related to the UI flexibility provided by jQuery.

So, I have decided to run down a simple example for all of you where we will utilize jQuery in ASP.NET application to fetch the Server Side DateTime. Note that we will be developing this demo application in ASP.NET 1.1, to prove a point that how easy it is to integrate jQuery in already deployed application as compare to ASP.NET AJAX.

Some of the Pre-requisites, you should care about is the one and only jQuery library itself. You can get the library from here jQuery Download [http://jqueryui.com/download]. One great thing you will notice, when you will go to download section; it allows you to select/deselect different features of the framework along with theme selection as well. This feature helps the developer to avoid bulky packages and be functionality centric. You should also bookmark the website, as you will need it later on for different knowledge base articles regarding the framework. Also, the forums and discussion boards are very active and usually you get the response to your questions quite quickly.

Coming to the demo, first we have to include the jQuery library in the default.aspx

<script type=”text/javascript” src=”jquery-1.1.js”>

First we will define the action which will get triggered when user will click on “Get Server Time”

$(function() {
    $(“a#runSample1″).click(function() {
        $.get(“GetServerTime.aspx”, function(response) {
            alert(response);
         });
    });
});

For your reference, let’s take a look at when we just did.

This code will be executed on page onload event.

$(function() {

This  code, we are binding an event with the “onclick” event of the hyperlink. Which user will click?

$(“a#runSample1″).click(function() {

The above code allows us to define that, when user clicks the link “Get Server Time”, the action will get fired and will call a proxy page which we will create later on. That proxy page will return the server time into the response object which we just mentioned in the above code. And it will be displayed in message box.

$.get(“GetServerTime.aspx”, function(response) {
    alert(response);
});

Now proceeding to the proxy page “GetServerTime.aspx”. On this page, we don’t need the HTML. Therefore, we will only keep the top declaration and will remove rest of the HTML

<%@ Page Codebehind=”GetServerTime.aspx.cs” AutoEventWireup=”false” Inherits=”AJAXJQuerySample.GetServerTime” %>

The code behind of the proxy page will be

private void Page_Load(object sender, System.EventArgs e)
{
    Response.Expires = -1;
    //required to keep the page from being cached on the client’s browser
    Response.ContentType = “text/plain”;
    Response.Write(DateTime.Now.ToString());
    Response.End();
}

In the page_load method, Response.Expires = -1, allowes us to make sure that page wont get cached in the browser.

Response.ContentType = “text/plain”;
Response.Write(DateTime.Now.ToString());
Response.End();

The above code just set the content of the response to plain text and writes the current time to the response stream.

This is it. Now, we can run our sample application and click the “Get Server Time” link, this should give us the current time in an alert box:

Demo Screenshot

Hope this will be hlpful to get you started. Let me know about it.

Waqas Ahmed

To start, today I have picked LINQ. Language Integrated Query aka LINQ, is all about achieving query operations in a well comprehensive and open form. It allows you to query data regardless of any type, May it be relational databases, XML or Objects. Considering this phenomenon of querying across any kind of data source, this will be a great breakthrough and major shift in how our programmers deal with data related tasks. Having the possibility at your fingertip to query any kind of data will really change the way we program.

LINQ provides a set of patterns for querying any kind of data, whether it has a particular object model implemented or not. LINQ specifies how an object can be a “queryable,” with all the basic query operations needed, like: SELECT, WHERE, GROUP BY, ORDER BY, JOIN along with many other new operations like SelectMany, GroupJoin, TakeWhile, SkipWhile, ElementAt etc.

The syntax is the part where the real ease and flexibility shows up. You can have any language, that is supported on .Net Platform;  to be able to support LINQ.  C# and VB.NET has this built in features to interfacing LINQ. An example, where you have an array of Employees objects and you want a name of an employees having salary greater then 10000, you can write this query that looks like this:

var query_results =  from c in Employees
                                           let sal = 10000
                                           where c.Salary < sal
                                           select c.Name;

foreach (var result in query_results)
{
          Response.Write(result.ToString());
}

The above example mimics a scenario for a relational database. What happens if we have a dynamic data source like an RSS feed? Here is the simple example for that

XElement orders = …;
int order_amount = Convert.ToInt32(orders.Element(“amount”));

As you have seen that, LINQ is a way to go for data related operations due its flexibility and its data source independence. I have tried to give you an overview of LINQ but there are whole lot of information and resources available for you to get your hands dirty in LINQ . I’m including some of the references below for your help:

• http://en.wikipedia.org/wiki/Language_Integrated_Query#Language_Extensions
• http://msdn.microsoft.com/en-us/netframework/aa904594.aspx
• http://msdn.microsoft.com/hi-in/library/bb308960(en-us).aspx

Happy Reading

Waqas Ahmed

• LINQ extension for VB 9.0 and C# 3.0 language provides a set of standard query operators to query many different kind of data sources using SQL like syntax. This extension for VB and C# implements LINQ pattern.
• LINQ to Object is the default implementation for LINQ. It enables the developer to execute queries against a data persisted in memory that implements IEnumerable or IQueryable interface.
• LINQ to SQL extension to LINQ to Objects provide an O/RM tool to generate and manage classes for business objects and to persist their instances in SQL Server tables.
• LinqDataSource server control introduced in ASP.NET 3.5 simplifies the headache to bind data enabled web controls to business objects created with LINQ to SQL.

Later on we will discuss each of the above mentioned extensions individually, to look under the hood of ADO.NET 3.5 and it’s working.

Until than happy reading

Waqas Ahmed

• Increase developers productivity with minimal code required to achieve certain database/data related tasks.
• Allow strong-type checking of database query syntax for relational data and their resultsets.
• Enhancements to DataSet integration with multi Tier application architecture.
• Enabled data intensive Winform projects with a local, synchronizable data cache derived from SQL Server Compact Edition v3.5
• Enabled data intensive Winform projects with a local, synchronizable data cache derived from SQL Server Compact Edition v3.5.
• Eliminate often known as the resistant mismatch between the code for data management, which usually involves SQL and OOPs programming.

Next time we will talk about the introduction of different extensions to LINQ related components /frameworks.

Waqas Ahmed

It’s a language that builds upon the architecture of the web and the principles of isolation, actors, and message-passing to increase application safety, responsiveness, scalability and developer productivity. Other advanced concepts we are exploring are data flow networks, asynchronous methods, and type annotations for taming side-effects. 

You can get Microsoft Axum from http://www.microsoft.com/downloads/details.aspx?FamilyID=CFE70D5D-37AA-4C4C-8EEB-D4576C41BAA2&displaylang=en

Waqas Ahmed