.NET Evangelist - Abi Bellamkonda

System.Data.SqlClient.SqlClientPermission

2006-02-13T10:58:00.000+11:00

You get the follwoing error when cconnecting to a SQL Server database from a Win App in .net 2.0 sometimes.

Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

A quick search on google showed http://www.vbcity.com/forums/topic.asp?tid=105907&#RID380236. All you need to do is just

open solution explorer-->Click Project Properties--> Click Security tab-->Tick 'Enable ClickOne Security settings'.
Ensure you have selected 'This is a full trust application', or appropriate security settings.
Recompile and run.

Gmail For Your Domain

2006-02-13T10:27:00.000+11:00

Google is looking for organizations to beta test its new hosted email service. From the information page: 'This special beta test lets you give Gmail, Google's webmail service, to every user at your domain. Gmail for your domain is hosted by Google, so there's no hardware or software for you to install or maintain.' The beta test is limited, but Google is accepting open applications. I am excited about Google buy and this hosted mail service.

Invalid Cast Exception XMLElement

2006-02-09T16:44:00.000+11:00

You wrote a class say StoredItemElement, that inherited from XmlElement class. When you open the document and try to cast the Element to StoredItemElement, you get an exception "Cannot cast 'this.SelectSingleNode("/WorkFlow/Messages")' (which has an actual type of 'System.Xml.XmlElement') to 'Roadhouse.WorkFlow.Engine.Messages'". In other words its "Specified cast is not valid" exception. Then do the following... 1. Don't use XmlDocument, write a class, say StoredElementDocument : XmlDocument 2. Override the CreateElement method in StoredElementDocument as below.. public override XmlElement CreateElement( string prefix, string localname, string namespaceuri ) { switch(localname) { case "StoredItemElement": return new StoredItemElement(prefix, localname, namespaceuri, this); // ..... Any other XmlElements default: return base.CreateElement(prefix, localname, namespaceuri); } } 3. Use StoredElementDocument instead of XmlDocument

StoredElementDocument  doc = new StoredElementDocument();
doc.Load("File.xml");
StoredItemElement element =
(StoredItemElement)doc.SelectSingleNode("//StoredItem");

404 NET framework IIS6

2006-02-06T12:54:00.000+11:00

I received 404 when i tried to open a ASP.NET app, after installing 1.1 & 2.0 frameworks on a virtual machine. To my suprise the following solution worked.

Open IIS
Expand [COMPUTER NAME]--> Web Service Extenstions
Select ASP.NET frameworks and click 'Allow'

Imagine Cup 2006

2006-02-02T10:50:00.000+11:00

There is a new competition going on now, called Imagine Cup 2006. Ohhh, i still haven't started working on TopCoder Intel competition yet. The following is an extract of what is available in the competition.

We are working with Universities to integrate the Imagine Cup Software Design Invitational into course work for Semester 1 2006. The theme for Imagine Cup 2006 is "imagine a world where technology helps us to live healthier lives". We could integrate this as an assignment or project for next year. The winning team and lecturer from Australia will be flown to the worldwide finals in Delhi, India next year to win up to USD$25,000 in the software design category.

If you are interested in integrating and promoting Imagine Cup 2006 please email netoz@microsoft.com

Software Design Invitational

The Software Design Invitational challenges students around the globe to explore their own creativity by using technology to solve what they consider to be challenging problems. Imagine Cup provides a theme but the competitors provide the genius behind innovative, dynamic, and powerful software applications. Using Microsoft tools and technology, competitors can unleash their ideas, their curiosities, and their talents towards creating usable software applications. Competitors are asked to demonstrate innovation on the .NET Framework and Windows platform but the possibilities only begin with these requirements. Globally, students in this invitational conceive, test, and build their ideas into applications that can change the world. Many former winners go on to start their own companies, work at major corporations, and even integrate their projects into how their schools approach teaching.

General Guidelines

Teams of up to 4 individuals

Theme: Imagine a world where “technology helps us to live healthier lives”

Presentations and documentation at the WW finals must be in English, first and second rounds are subject to language requirement set by the Microsoft subsidiary you compete within.

Required Elements

Self created Web service

Designed on .NET Framework 2.0

Use of Visual Studio family (Express, Standard, or Team System) for development

Optional Elements

Mobile device

.NET Compact Framework

ASP .NET

SQL Server

Deliverables

Application executables and readme files

Project specification, no more than 5 pages

One page executive summary

Oral presentation – length TBD based on number of qualifying teams

Visual representation of system architecture

Judging Elements

15% Problem Definition

How difficult is the problem being addressed? How well is it being defined?

60% Design

Equal consideration will be given to:

Innovation – applications that approach a new problem, or look at an old problem in a new way.
Impact - applications that either impact a large number of people very broadly, or impact a smaller number of people very deeply.
Effectiveness – to what degree the application actually solves the problem in question.

15% Development

The judges will be looking for elegant system architectures that break the problem down into logical chunks and modules.

10% Presentation

The judges will be looking for oral presentations that provide background and context to the project, explain why the problem is an interesting one, highlight how the system works, and include an insightful demonstration. Teams will also be evaluated on their ability to take questions from the judging panel.

Scoring System

A simple numerical scoring system will be used. Each Judging element will be given a score of 1-10 and weighted according to guidance seen in the percentages associated with each.

Requirements to Reach Worldwide Finals

Participants must have built and presented a running software application that won a national or regional level competition in a country or region that is sponsoring a winning team for the worldwide Imagine Cup finals.

Prize Amounts for Worldwide Finals

First Place $25,000

Second Place $15,000

Third Place $10,000

Additional prizes: Competitors that achieve advancement to the worldwide finals will also receive travel and accommodations to attend the final competition in Delhi, India.

Intel Code Competition

2006-01-24T22:04:00.000+11:00

Intel® Software Network Multi-threading Competition Series

Intel are holding a competition at http://www.topcoder.com/intel. This is aimed at developing multi threaded applications on multi processor computers. This will occur during a 12 month period. Each competion will last for 2 weeks. You could win Monthly Cash Prizes: Champion - $2,500 2nd Place - $1,000 3rd Place - $750 4th Place - $500 5th Place - $250 First match starts 26th Jan 2006. Testing will be on the following machines

Let the Games Begin !!

Difference in File uploads in .NET 2.0

2006-01-23T14:44:00.000+11:00

Uploading multiples file was not too easy in .NET 1.1 framework. In .NET 2.0 they have introduced something called "Request.Files".

Request.Files

This is what you have to do if you want to upload multiple file in .NET 2.0 framework


HttpFileCollection uploadedFiles = Request.Files;
for (int i = 0; i < uploadedFiles.Count; i++)
{
 HttpPostedFile userPostedFile = uploadedFiles[i];
 userPostedFile.SaveAs(Server.MapPath("~/Downloads/") + System.IO.Path.GetFileName(userPostedFile.FileName)));
}

LDAP Attributes list

2006-01-20T09:43:00.000+11:00

This link http://www.computerperformance.co.uk/Logon/LDAP_attributes_active_directory.htm has a good list of Active Directory attributes. The good thing about this is that it shows us the corresponding screens in Active Directory while showing the attribute names.

Difference between OVER(), RANK() and DENSE_RANK()

2006-01-13T11:45:00.000+11:00

I came across this article at 4GuysFromRolla. They spoke about OVER, RANK, DENSE_RANK in SQL Server 2005. SQL brought in these functions (oh yeah oracle had it since i was wearing nappies). Though i used RANK's in Oracle, i didn't really understand the difference before.

OVER - gives sequential numbers
RANK - gives ranks to records, so more than a record may have same rank
DENSE_RANK - same as ranks, but will continue the ranking number, but rank will skip ranks when more than a record gets same rank.

Paging in SQL Server 2005

2006-01-13T11:18:00.000+11:00

Oracle has ROWNUM column which will let us select paged records(gets you 21-30 records) by using the following query. SELECT * FROM (SELECT RowNum, P.* FROM Products P) As T WHERE T.RowNum BETWEEN 21 and 30 SQL Server 2000 didn't have this feature. Paging in SQL Server 2000, was a pain, we had to build dynamic SQL to do the paging or use temp tables.

SQL Server 2005 has "RowNum" now

Its better to be late than never. This following query will give us the records from 21-30. Both 21 and 30 can be replaced by @Start and @End variables.


SELECT * FROM
(SELECT ROW_NUMBER() OVER (ORDER BY Title DESC) AS RowNum, *
FROM         Product) As P
WHERE     RowNum BETWEEN 21 AND 30

Also SQL Server 2005's TOP keyword takes variables now. I was used to a solution similar to a comment at http://weblogs.sqlteam.com/jeffs/archive/2003/12/22/672.aspx#1524. Now we can do this instead of dynamic SQL.


SELECT * FROM
(SELECT TOP @PageSize ROW_NUMBER() OVER (ORDER BY Title DESC) AS RowNum, *
FROM         Product) P
WHERE P.RowNum> @PageSize * (@PageNumber-1)

You still need ROW_NUMBER, unless you sort other way round.

Canvas Tutorial

2006-01-13T11:16:00.000+11:00

Canvas

Canvas is a HTML element that is planned to be introduced in HTML 5. Canvas is like a blackboard where we can draw (paint) any kind of Art we want. This is currently available in FireFox, you can do the following stuff (Its similar to GDI in .NET). Canvas tutorial is available here http://developer.mozilla.org/en/docs/Canvas_tutorial:Applying_styles_and_colors#Transparency

Different types of line caps
Arcs and sectors
Callout symbols using quadraticCurveTo() method, we can draw lines and other shapes too
Drawing up nice shapes using arcs & circles.
Drawing symetric shapes
Coloring them
Radial Gradient filling
Filling regions and lines with Linear Gradients
Drawing Arcs with diiferent colors & Alpha values
Animate them all
Using images to show like Art Gallery

Top Coder Open 2006 Begins !

2006-01-05T13:13:00.000+11:00

The Games have begun !

Oh yes, prize money is USD $150,000 this time. As usual, they have algorithm, design and development competitions this time. Algorithms can be written in C#, VB.NET, Java or C++. But mind you, its NOT easy. We have to get the things right, within the given time frame. You can parctice algorithms question in Top coder. The competition is held at http://www.topcoder.com/tc?module=Static&d1=tournaments&d2=tco06&d3=about

Ajax Ian

2006-01-03T15:57:00.000+11:00

I found this useful blog. They are giving tons of useful User Interface information. Targetting usability/cross browser stuff. Their URL is

http://ajaxian.com/

XUL Challenge

2005-12-28T12:37:00.000+11:00

There was a recent XUL challenge at http://www.sourceforge.net , they show cased many extensible User interfaces. They all had to develop a little application using different extensible User interfaces.

The Unnoticed .NET 2.0 Standard controls

2005-12-28T10:38:00.000+11:00

We have noticed many new controls in .NET framework 2.0, like DataSources and GridView, DetailsView, Tree, ObjectDataSource, SiteMap, Web parts and so on. I found some controls have gone unnoticed.

MultiView and View

MultiView control composites multiple views, developer can set the ActiveViewIndex when required. This has got it purpose, as there are several instances where we have multiple views, but we have to show a view to a user based on User's access and views are very different to each other. We typically used to achive this using Panel controls and setting their visibility property to true/false. A typical multiView control can look like...


<asp:multiview id="MultiView1" runat="server" activeviewindex="0">
    <asp:view id="View1" runat="server">
        Now showing View #1<br />
        <asp:textbox id="TextBox1" runat="server"></asp:TextBox><strong> </strong>
        <asp:button id="Button1" runat="server" text="Button"></asp:View>
    <asp:view id="View2" runat="server">
        Now showing View #2<br />
        <asp:hyperlink id="HyperLink1" runat="server" navigateurl="http://www.asp.net">HyperLink</asp:HyperLink>
        <asp:hyperlink id="HyperLink2" runat="server" navigateurl="http://www.asp.net">HyperLink</asp:HyperLink></asp:View>
    <asp:view id="View3" runat="server">
        Now showing View #3<br />
        <asp:calendar id="Calendar1" runat="server"></asp:Calendar>
    </asp:View>
</asp:MultiView>

We can set the active view by the following


MultiView1.ActiveViewIndex = DropDownList1.SelectedValue

Substitution

Substitution is useful when you have a Page/UserControl that is cached, but you want somethings to be dynamic. Substitution enables us to do this. In past we choose not to cache as one of the option. or to split the Page/UserControl intto multiple UserControls. In the below example the cached time will change every 60 seconds, but Substitution time changes for every request.


<%@ Page Language="C#" %>
<%@ OutputCache Duration="60" VaryByParam="none" %>

<script runat="server">
static string GetCurrentDate(HttpContext context)
{ return DateTime.Now.ToString(); }
</script>

<form id="form1" runat="server">
Cached Time:<%= DateTime.Now.ToString() %>
Substitution time: <asp:Substitution ID="Substitution1" runat="server" MethodName="GetCurrentDate" />
</form>

Its is intesting to note that these methods take HttpContext as argument, which is reasonable, as that's required in most cases. We can also use Response.WriteSubstitution (new HttpResponseSubstitutionCallback(GetCurrentDate)) method to do the same too. It looks like we can get most of the string stuff. I have to explore if we can use Substitution for DataGrid or so on.

Wizard

Wizard is an other Standard control, it delivers forms in Wizard style. I will try not to use this, as when you say Wizard, it means you have a big form, which implies that users are not going to visit the site, as you might expect. Forms should be as simple as possible (KIS = keep it simple). There is lot said about Wizard at http://beta.asp.net/QUICKSTART/aspnet/doc/ctrlref/standard/wizard.aspx

The request failed with HTTP status 407: Proxy authentication required

2005-12-02T14:37:00.000+11:00

My wife developed a ConsoleApp that communicates to a Web Service which was deployed at client site later. The ConsoleApp gave a problem

The request failed with HTTP status 407: Proxy authentication required

When we googled for this problem, we found the link http://support.microsoft.com/default.aspx?scid=kb;en-us;330221 which instructs us to set the proxy settings as below...


WebProxy myProxy = new WebProxy("http://proxyserver:port",true);
myProxy.Credentials = new NetworkCredential("username", "password", "domain");
FindServiceSoap myFindService = new FindServiceSoap();
myFindService.Proxy = myProxy;

I won XBox 360 & Xbox 360 Game !!!

2005-11-28T21:36:00.000+11:00

I won XBox 360 & Xbox 360 Game !! It says Abishek Bellamkonda from Melbourne, Australia, using Grasshopper Abishek used Grasshopper for the port and said "I had a few hiccups, but for the most part, Grasshopper did the work for me." Abishek ported both the Time Tracker and Reports kit and said the first port took a couple of hours and the second one took about 30 minutes or so, including through testing.

Abishek won an Xbox 360 and a game of his choice.

Roadhouse made an offer

2005-11-28T21:20:00.000+11:00

Adam gave me a call for a chat and asked if i am intrested to come back to Roadhouse and made a good offer. I accepted it gladly. Its all good, the bad thing is that my wife works at same company.

Finished the DAMN part-time Masters degree exams

2005-11-21T23:25:00.000+11:00

Ok today was my last exam for my part-time Masters degree course. Now i will get some time for code competitions and other stuff. Went partying around today.

DotLucene

2005-11-12T16:53:00.000+11:00

A colleague pointed me to an software that searches stuff. Obviously I explored the files available and found DotLucene, which is currently "The Fastest Open Source Fulltext Search Engine for .NET". It basically will index documents and retrieve them on request. The results are pretty good. Its worth using it. It can be used, customised in many projects.

My own Find

2005-10-31T15:47:00.000+11:00

My own custom client side find functionality for IE.


<input type="text" id="SearchText" value="the">
<input type="button" onclick="doFind(SearchText.value, searchableText);" value="Find">
<INPUT onclick="clearFind(SearchText.value, searchableText);" type="button" value="Clear" name="ClearSearchButton">


var HIGHLIGHT_START = "";
   var HIGHLIGHT_END = "";
   function doFind(text, elementToSearch)
   {
    var re = new RegExp(text, "ig");
    elementToSearch.innerHTML = elementToSearch.innerHTML.replace(re, HIGHLIGHT_START + text + HIGHLIGHT_END); 
   }

   function clearFind(text, elementToSearch)
   {
    var re = new RegExp(HIGHLIGHT_START + text + HIGHLIGHT_END, "ig");
    elementToSearch.innerHTML = elementToSearch.innerHTML.replace(re, text);
   }

This is a working version

Authorities have detected signs of bird flu at a farm in northern Japan and plan to kill 82,000 chickens, local officials say. The farm in Ibaraki prefecture, just north east of Tokyo, was already inside a quarantined area because of past outbreaks, Kyodo News agency reported. Kyodo said 1.5 million birds had already been culled in the area because of bird flu fears. Authorities found signs of the disease in seven farms in the area at the end of August. In today's case, antibody tests showed the chickens may be infected with a virus from the H5 family, Ibaraki prefectural officials said in a statement. Signs of the antibodies means the chickens were infected in the past but had survived. Japanese officials said the strain involved in the recent outbreaks is less virulent that the H5N1 variety that has ravaged poultry in South-East Asia since 2003 and killed more than 60 people in Vietnam, Thailand and Cambodia. Bird flu hit Japan last year for the first time in decades, killing or prompting the extermintion of hundreds of thousands of chickens. Japan also confirmed a human case of bird flu in December 2004, but no deaths have been reported. An outbreak in June forced the culling of about 94,000 birds at another farm outside Tokyo. It was caused by the H5N2 bird flu strain, a variety not known to infect humans.

Some	text
is	available
in	the
a	Table

Xaml

2005-10-21T15:47:00.000+10:00

I had my university assignments recently. One of the assignment in Advanced .NET subject was to develop a multi-threaded Application to simulate a car park. I wanted to score as much as i can, and the lecturer Andrew Cain has allocated bonus marks for the subject when someone does something intresting. I wanted the interface to look good, i knew that using vector graphics will make UI better. Doing a quick google i came accross a Xaml. Xaml is used to define User interfaces using markup. More information on Xaml can be found at http://www.xaml.net/ and http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnintlong/html/longhornch03.asp Marc Clifton has a website called http://www.vgdotnet.com/ that provided .NET libraries to produce User interfaces using Xaml. It provides a lite version and a full version. Lite was sufficent for me. The above image shows how we can develop buttons with gradients. The below image show a Clock and calculator Application that we developed as Controls using Xaml. This site has something called Translucent forms, which will make the UI even better as shown below...

I'm think not to develop normal classic Windows Applications anymore. I want to use Xaml as much as possible.

Time Tracker

2005-09-24T01:27:00.000+10:00

I took part in the "Race To Linux" and submitted a Grasshopper port of ASP.NET Starter Kit's 'Time Tracker' project. I had to write up an article on the approach, which is located at http://www.codeproject.com/useritems/TimeTracker_Porting.asp

w3wp high usage IIS on Windows 2003

2005-09-02T16:58:00.000+10:00

Intresting... IIS on 2003 will show high usage (100%). And the fix is at http://support.microsoft.com/?id=894484. Looks like something to do with vunerability. It looks like it is to do with the asp.dll

Who fires events in WebForm?

2005-09-02T14:12:00.000+10:00

This was a reply to a post from someone on dotnetjunkies. It says "There are events like Page_Load, OnPreRender, and so on events, who fires it, exactly. Don't say .NEt framework, it is like Universe. Be specific." Obviously this person wants exact answers and looks like got the passion for understanding unknown. Ok in simple terms it is Control. In .NET we have the concept of Controls. A control can have many child controls, they can have any number of child controls and so on. It is Composite Pattern (GOOGLE for it, if you are intrested). Now each control should be rendered to client, during this process we have several events. Firstly we need to Initilize, Load, CreateChildControls and finally render. So the same controls will fire all these events for themselves. Again child controls will do the same firing. For example if you take DataGrid, it will have many rows, which has many cells, which inturn might have controls (buttons, labels and so on). They implemented it nicely using Composite Pattern. Now intresting part is even the System.Web.UI.Page class is a Control too (it inherits from Control, if you look at the class heirarchy). There are many other events apart from the ones mentioned above like Loading of ViewState, saving ViewState bla bla.