Numeric textbox javascript...

    <input type='text' onkeydown='text_keydown(event)' />

    <script language='javascript' type='text/javascript'>
    function text_keydown(e) 
    {
        var key; 
        document.all ? key = e.keyCode /*IE*/ : key = e.which /*FF*/; 
        if(!(key > 47 && key < 58) && key != 8 && key != 37 && key != 39 && key != 16 && key != 46)
        {
            cancelevent(e);
        } 
    }

    function cancelevent(e)
    {
        if(window.event)    // IE
        {
            window.event.returnValue = false;
        }
        else    // FF
        {
            e.preventDefault();
        }
    }
    </script>

What's new in Ubuntu 10.10...

1) Simpler Installer.
Ubuntu 10.10 is expected to use a new installer that makes the installation process simpler than ever. Startup options are now placed right in the installer itself, and they include just two options: Try Ubuntu and Install Ubuntu. A simplified partitioner, meanwhile, lets users choose between automatically using the whole disk and manual partitioning, while a new Wireless Network Selection page will be added as well. These features will be particularly helpful for newer Ubuntu users.

My response:
I've started with 6.10 (Edgy Eft) and never felt it's difficult to install Ubuntu (it's the same 6 clicks process, except for the partitioning part might be a little bit tricky for newbie). Overall installing desktop Linux couldn't be more difficult than Windows unless if you're talking about pre Red Hat 7 era in 90s.

2) Processor Support.
It sounds like the Maverick Meerkat will not run on processors older than i686, or anything before Intel's P6 microarchitecture. For most business users this probably won't be an issue, but it could affect some occasional users of older machines.

My response:
I don't need to worry about this because I don't have that kind of old machine. :)

3) Default Environment and Applications.
Ubuntu 10.10 Beta uses version 2.6.35.3 of the Linux kernel, which includes numerous security enhancements over previous versions. It also updates the GNOME desktop environment to version 2.31.

Among application changes, meanwhile, is that Firefox 3.6.8 will be the default, as will OpenOffice 3.2.1, for example. Photo tool F-Spot has been replaced with Shotwell, while a new sound indicator has been enhanced to include music player controls.. The Evolution mail and collaboration software will be updated to the 2.30.2 version, which reportedly is much faster than the one in Ubuntu 10.04 LTS, or Lucid Lynx.

My response:
I never use F-Spot and Evolution mail. For image editing, Gimp is my preference. Sound indicator to include music player controls sounds cool to me.

4) The Ubuntu Software Center
In version 10.10, the Ubuntu Software Center--the tool for browsing, installing and removing software on Ubuntu--will gain "Featured" and "What's New" choice icons on the front page, along with a "History" tab displaying recently installed software. It is also said to be faster and more responsive. Taken together, these improvements promise to make it much easier to track and find new software options.

My response:
This should be interesting. Might change to this instead of Synaptic.

5) Multitouch
Making the biggest splash, of course, will be the new multitouch and gesture capabilities, which will apparently make it possible for basic gestures to be chained, or composed, into more sophisticated "sentences." Toward that end, Canonical has created an open source gesture recognition engine and defined a gesture API that provides a way for applications to respond to users' gestures.

Canonical is currently targeting the Dell XT2 as a development environment for this new feature, but by release it expects it to be compatible with a range of devices from major manufacturers, and with add-ons like Apple's Magic Trackpad. Needless to say, this will pave the way toward a host of new capabilities on the Linux desktop and beyond.

My response:
Unfortunately I don't have any hardware with the capability to benefit this feature.

Note:
Text copied 97% from PCWorld news with a reference to The Fridge.

VB.NET vs C#, why bother? We're .NET developers after all...

I can't believe that people are still debating on this topic. While searching for anonymous methods in VB.NET, I came across to this article "Top 10 reasons VB.NET is better than C#". It was posted on August 23rd 2004 and the last comment was on August 31st 2010!!!

Update:
Did a search further with keyword "vb.net vs c#" and found out that there's another article from the same person on the same day, but this time it's the other way around. "Top 10 reasons C# is better than VB.NET".

Exposing DTO to javascript in ASP.NET...

This post is a continuity from my previous post related to Calling a webservice from javascript in ASP.NET 2.0. Fundamentally it's sharing the same concept. This time I've written the code in ASP.NET 3.5 (Visual Studio 2008). There's no prerequisite required compare to when I did it in ASP.NET 2.0 (Visual Studio 2005).

Once I knew how to call a webservice from javascript in ASP.NET (regardless of version). I've search google to check whether it's possible to pass an object as a parameter to webservice method. Indeed it is possible to do that, but I must make sure that the object should be simple enough without any business logic and with limited behaviour. The object known as Data Transfer Object or in short DTO. Now here's the step by step on how to do it.

1) Using Visual Studio 2008, create new web site. Select ASP.NET Web Site.

2) To create DTO object, add new class under App_Code folder. Lets name it as Student. Paste the code below.

    using System;

    /// 

    /// Summary description for Student
    /// 
    public class Student
    {
        public Student()
        {
        }

        public string Id
        {
            get;
            set;
        }

        public string Name
        {
            get;
            set;
        }
    }

3) Create new webservice call MyWebService. Add System.Web.Script.Services namespace then add GenerateScriptType and ScriptService attribute to the webservice class. Notice that what I did here is almost the same as my previous post. The only extra code is at line 7 which is to expose Student class to javascript.

    ...
    using System.Web.Script.Services;

    /// 

    /// Summary description for MyWebService
    /// 
    [GenerateScriptType(typeof(Student))]
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ScriptService]
    public class MyWebService : System.Web.Services.WebService 
    {
        ...
    }

4) Add two methods call GetStudents and TestSubmit. GetStudents method will return a list of students to the caller. Since I want to return it as a JSON object, I've set the ResponseFormat to JSON.

    ...
    [WebMethod]
    [ScriptMethod(ResponseFormat=ResponseFormat.Json)]
    public List<Student> GetStudents() 
    {
        var students = new List<Student>();

        for (int x = 0; x < 10; x++)
        {
            students.Add(new Student 
                { 
                    Id = x.ToString(), 
                    Name = "Name" + x.ToString() 
                });
        }

        return students;
    }

    [WebMethod]
    public string TestSubmit(Student student)
    {
        return String.Format("You've submitted Student object with Id: {0} and Name: {1}", student.Id, student.Name);
    }

5) Go to Default.aspx, add ScriptManager (again another same step as my previous post in ASP.NET 2.0).

    ...
    <asp:ScriptManager ID="ScriptManager1" runat="server">
        <Services>
            <asp:ServiceReference InlineScript="true" Path="~/MyWebService.asmx" />
        </Services>
    </asp:ScriptManager>
    ...

6) Now add the html control

    ...
    <div>
        <input id="btnLoad" type="button" value="Get Students" onclick="javascript:btnLoad_Click();" />

        <input id="txtId" type="text" /><input id="txtName" type="text" />
        <input id="btnSubmit" type="button" value="Submit" onclick="javascript:btnSubmit_Click();" />

        <table id="myTable" border="1" cellpadding="1" cellspacing="1"></table>
    </div>
    ...

7) and the javascript

    ...
    <script language="javascript" type="text/javascript">
    function btnLoad_Click()
    {
        try
        {
            MyWebService.GetStudents(OnGetStudentsComplete);
        }
        catch(e)
        {
            alert("error " + e);
        }
    }

    function OnGetStudentsComplete(result)
    {
        var htmlVal = "";

        for(var x=0; x<result.length; x++)
        {
            htmlVal += "<tr><td>" + result[x].Id + "</td><td>" + result[x].Name + "</td></tr>";
        }

        $get("myTable").innerHTML = htmlVal;
    }

    function btnSubmit_Click()
    {
        try
        {
            var stu = new Student();
            stu.Id = $get("txtId").value;
            stu.Name = $get("txtName").value;

            MyWebService.TestSubmit(stu, OnTestSubmitComplete);

            var htmlVal = $get("myTable").innerHTML;
            htmlVal += "<tr><td>" + stu.Id + "</td><td>" + stu.Name + "</td></tr>";
            $get("myTable").innerHTML = htmlVal;
        }
        catch(e)
        {
            alert(e);
        }
    }

    function OnTestSubmitComplete(result)
    {
        alert(result);
    }
    </script>

Now I have a web site that can call a webservice and passing an object as a parameter via javascript.

Evolution of data query in C#...

One of the most common operation in programming is data query. In C# 1.2, normally I would use a custom collection class that derived from System.Collections. But for sake of example here, I'll show it with an ArrayList instead.

Here's a class that'll become an element of the collection (yes, I know Auto-Implemented Properties).

    public class Student
    {
        private int _id;
        private string _name;
        private string _gender;

        public Student()
        {
        }

        public int Id
        {
            get { return _id; }
            set { _id = value; }
        }

        public string Name
        {
            get { return _name; }
            set { _name = value; }
        }

        public string Gender
        {
            get { return _gender; }
            set { _gender = value; }
        }
    }

This is how I normally code in C# 1.2 (.NET Framework 1.1) with an ArrayList.

    private ArrayList SomeFilterMethod(ArrayList myList)
    {
        ArrayList result = new ArrayList();
        
        for (int x = 0; x < myList.Count; x++)
        {
            if (((Student)myList[x]).Gender == "Male")
            {
                result.Add(myList[x]);
            }
        }

        return result;
    }

Generic list with action and predicate was introduced in C# 2.0 (.NET Framework 2.0). This is how my code will look like.

    private List<Student> SomeFilterMethod(List<Student> myList)
    {
        return mylist.FindAll(GetMaleStudents); 
    }

    private bool GetMaleStudents(Student item)
    {
        return item.Gender == "Male";
    }

Not to forget an anonymous methods.

    private List<Student> SomeFilterMethod(List<Student> myList)
    {
        return mylist.FindAll( delegate(Student item) { return item.Gender == "Male"; } ); 
    }

In C# 3.0 (.NET Framework 3.5), there's LINQ with 2 flavours.
1) Lambda Expression

    private List<Student> SomeFilterMethod(List<Student> myList)
    {
        return mylist.FindAll( item => item.Gender == "Male" ); 
    }

2) Query Expression

    private List<Student> SomeFilterMethod(List<Student> myList)
    {
        return (from student in mylist
            where student.Gender == "Male"
            select student).ToList<Student>();
    }

Between the two, personally I prefer the former.

Huawei modem undetected on Ubuntu 10.04...

Scenario:
Plug-in modem, Ubuntu detect it as data storage only instead of modem. Only happen on Ubuntu 32bit, working as expected on 64-bit version.

Solution:
Install usb-modeswitch package.

    $ sudo apt-get install usb-modeswitch

Note:
Tested on Ubuntu 10.04 32-bit Desktop and Netbook Edition.

Calling a webservice from javascript in ASP.NET 2.0...

Prerequisite:
In Visual Studio 2005, to make a web project template available, you need to upgrade to SP1. The "other alternative" is to install VS80-KB915364-X86-ENU.exe and WebApplicationProjectSetup.msi. If you choose SP1 than ignore the "alternative" way.

1) For Ajax-Enabled Web Site, install ASP.NET Ajax 1.0.

2) Create new ASP.NET Ajax-Enabled Web Site.

3) Add reference System.Web.Extensions ver 1.0.61025.0.

4) On server side, create new WebService, add System.Web.Script.Services namespace and add ScripService attribute to your webservice class.

    ...
    using System.Web.Script.Services;
    ...

    [ScriptService]
    public class MyWebService : WebService
    {
        public MyWebService()
        {
            //Uncomment the following line if using designed components 
            //InitializeComponent(); 
        }

        [WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }
    }

5) On client side, create new web form and add ScriptManager to the aspx file that pointing to your webservice (MyWebService.asmx).

    ...
    <asp:ScriptManager ID="ScriptManager1" runat="server">
        <Services>
            <asp:ServiceReference InlineScript="true" Path="~/MyWebService.asmx" />
        </Services>
    </asp:ScriptManager>
    ...

6) Add an html button and its eventhandler.

    ...
    <input id="btnOk" type="button" value="Ok" onclick="javascript:btnOk_Click();" />
    ...

    <script language="javascript" type="text/javascript">
    function btnOk_Click()
    {
        try
        {
            MyWebService.HelloWorld(OnHelloWorldComplete);
        }
        catch(e)
        {
            alert("error " + e);
        }
    }

    function OnHelloWorldComplete(result)
    {
        alert(result);
    }
    </script>

Done!!! Your first Ajax-Enabled Web Site.

Here's the full source code:
MyWebService.asmx.cs

    using System;
    using System.Web;
    using System.Collections;
    using System.Web.Services;
    using System.Web.Services.Protocols;
    using System.Web.Script.Services;

    /// 

    /// Summary description for MyWebService
    /// 
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [ScriptService]
    public class MyWebService : WebService
    {
        public MyWebService()
        {
            //Uncomment the following line if using designed components 
            //InitializeComponent(); 
        }

        [WebMethod]
        public string HelloWorld()
        {
            return "Hello World";
        }
    }

Default.aspx

    <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
    <html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title>Untitled Page</title>
    </head>
    <body>
        <form id="form1" runat="server">
            <!-- to include webservice proxy, set inlinescript=true, it's much more easier compare to adding script src=webservice.asmx/js -->
            <asp:ScriptManager ID="ScriptManager1" runat="server">
                <Services>
                    <asp:ServiceReference InlineScript="true" Path="~/MyWebService.asmx" />
                </Services>
            </asp:ScriptManager>

            <div>
                <input id="btnOk" type="button" value="Ok" onclick="javascript:btnOk_Click();" />
            </div>
        </form>
    </body>
    </html>

    <script language="javascript" type="text/javascript">
    function btnOk_Click()
    {
        try
        {
            MyWebService.HelloWorld(OnHelloWorldComplete);
        }
        catch(e)
        {
            alert("error " + e);
        }
    }

    function OnHelloWorldComplete(result)
    {
        alert(result);
    }
    </script>