Random stuff

Version 0.6 of NGChart

noreply@blogger.com (digizzle) — Sun, 20 Jul 2008 12:33:00 +0000

New version of NGChart library supports QR codes.

From Google Chart API docs:

QR Codes are a popular type of two-dimensional barcode, which are also known as hardlinks or physical world hyperlinks. QR Codes store text which can be a hyperlink, contact information, telephone number, even whole verses of poems!

This is how encoded "Hello world" message looks like:

C# code for the image:

QRCodes chart = new QRCodes(new ChartSize(150, 150), "Hello world");

Updated NGChart library (.NET wrapper for Google Chart API)

noreply@blogger.com (digizzle) — Sun, 09 Dec 2007 20:10:00 +0000

NGChart was updated with the new features:

Bar charts

Pie charts with labels

Chart title

And the project wiki now has Samples page.

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.NET wrapper for Google Chart API

noreply@blogger.com (digizzle) — Fri, 07 Dec 2007 22:50:00 +0000

As you may know, Google created a simple and easy way to dynamically generate charts to use in web projects with the new Google Chart API.

I started a project to wrap the library to simplify usage of it in .NET projects.

As example - say, you need to visually compare two line charts:

Chart chart = new Chart(ChartType.Line,
                          new ChartSize(200, 125),
                          new ChartData(new int[][]
                                            {
                                                new int[] { 0, 1, 25, 26, 51, 52, 61, 1 },
                                                new int[] {7, 12, 60, 57, 4}
                                         }),
                          new Color[] { Color.DodgerBlue, Color.Gainsboro });
return chart.ToString();

It will generate the following url:

http://chart.apis.google.com/chart?cht=lc&chs=200x125&chd=s:ABZaz09B,HM85E&chco=1E90FFFF,DCDCDCFF

And the generated url shows the following chart:

del.icio.us tags: google chart, google, .net, c#, api, example, OSS, open source, chart

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Dell laptop and microphone problems

noreply@blogger.com (digizzle) — Sun, 16 Sep 2007 15:41:00 +0000

Suddenly, mic stopped working in my Inspiron 6400 Dell laptop. All audio devices are from SigmaTel, and non of my actions (like, turn on Microphone boost) did not help.

The soluiton I found - Go to Control Panel and Open SigmaTel Audio applet. It contains a single checkbox Allow reconfiguration Pop-Ups. You should check the box, and re-insert the microphone. You should see Audio System Event: "The system has detected an audion device connection event." Choose Microphone there and hit Ok.

Technorati tags: vista, microphone, problem, solution, troubleshooting, fix, mic, dell, laptop, sigmatel, inspiron 6400, audio

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Anonymous identification in ASP.NET 2.0 (nitpicking)

noreply@blogger.com (digizzle) — Mon, 27 Aug 2007 20:51:00 +0000

MSDN page on HttpRequest.AnonymousID says that the generated anonymous ID can be changed in AnonymousIdentification_OnCreate handler. But in reality you should use AnonymousIdentification_Creating handler (as it said in MSDN page on AnonymousIdentificationEventArgs class).

System disk cleanup (part 1)

noreply@blogger.com (digizzle) — Sat, 18 Aug 2007 10:57:00 +0000

Once a month I run out of free space at disk C: and everytime it's harder and harder to find what is safe to delete. I decided to create a list of temporary stuff which is safe to delete, and a list of utilities I'm using.

Before you start to delete files - it's a good idea to find out first who ate all the disk space. So you'll be sure you concentrated on the big files and folders. And get the required free disk space much faster ;)

Personally, I would recommend a great utility to visualise the disk usage - WinDirStat. It's open source software and hosted at SourceForge.net, free to use, small, fast and pretty simple - start it and select a disk drive you would like to analyze. In a minute you will have a tree of folders sorted by size. In addition it has "treemap" feature which gives you visual feeling of what and how is big.

Try it. I bet you'll find a lot of unused stuff.

This is a first part of "System Disk Cleanup" series.

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Send an email by GMail from ASP.NET 2.0

noreply@blogger.com (digizzle) — Thu, 21 Jun 2007 21:17:00 +0000

If you try to use ChangePassword control with GMail server in your settings, you'll probably get failed. To fix that you need to use SSL to send an email, and also - set SMTP server port to 587.

To use SSL add a handler to SendingMail event of the control with the following body:

protected void _ctrlPasswordRecovery_SendingMail(object sender, MailMessageEventArgs e)
{
        // send the same email, but with SSL enable
    SmtpClient client = new SmtpClient();
    client.EnableSsl = true;
    client.Send(e.Message);
 
        // cancel the sending by control
    e.Cancel = true; 
}

del.icio.us tags: ChangePassword, ASP.NET, .NET, SendingEmail, smtp, gmail, SSL, SmtpClient, mail, email

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Restore IntelliSense for web.config

noreply@blogger.com (digizzle) — Sun, 17 Jun 2007 15:45:00 +0000

Sometimes intellisense gets lost for web.config in VS2005.

Seems like it happens after usage of "ASP.NET Configuration" tool. The tool replaces <configuration> tag with <configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">, and IntelliSense is not available after that.

To fix the problem - just remove that xmlns="..." from the <configuration> tag. And save the web.config.

Technorati tags: vs2005, intellisense, web.config, problem, fix, asp.net configuration, configuration

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Fixing Visual Studio 2005 Documentation

noreply@blogger.com (digizzle) — Sun, 10 Jun 2007 14:37:00 +0000

Documentation for .NET Framework disappeared after I installed some additional stuff to VS2005 (I guess it was after "Web Client Software Factory - January 2007" installation). On hitting F1 in VS2005 usually I was getting "Information Not Found".

After unsuccessful searches in Google I gave up and decided to try to find the problem myself. That was funny, because I found the solution in a minute.

In case you have the similar problem I would suggest to try the following:

Run Microsoft Visual Studio 2005 Documentation from Start Menu. The Document Exproler should start with the page named The Visual Studio Combined Help Collection.
At the page click on Visual Studio 2005 Combined Help Collection Manager hyperlink. That should go to a page with information on all help collections installed at your machine.
Check all collections you need and hit Update VSCC. Close all instances of Document Explorer and VS2005. On the next start it will update indexes and you should get the help back.

Good luck.

Technorati tags: help, msdn, vs2005, vs, visual studio, index, repair, problem, fix

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Varozhka: Generation of a prediction set (part 4)

noreply@blogger.com (digizzle) — Fri, 15 Dec 2006 22:14:00 +0000

Now you should have Netflix dataset, Varozhka and a compiled test estimator at your machine. Please, check previous posts if you don't.

Before you start the processing I would recommend to unload all unneccessary stuff, because importing and processing are CPU- and memory- consuming tasks.

1. Run Varozhka.UI.exe. If this is a first run, it will ask you about settings:

You should provide:

Directory with the Netflix dataset.
Directory where prediction sets should be generated.
Assembly with an estimator (if you followed steps from the previous post it should be at C:\Projects\MyEstimator\bin\Release).

2. Indexing will start automatically if settings are valid:

This is a long operation... you can take a cup of coffee while it's importing. On my four years old P4 it takes around 40 minutes... a good place to optimize ;)

3. The main UI will appear after the indexing is completed. Here you can check RMSE against the current estimator:

And, if results are good - generate a prediction set to submit:

On complete it will start Submission page at Netflix Prize site, and will open Explorer window with the Output directory (you specified it in the Settings):

output.txt.gz is the Prediction file, and md5.txt contains md5 hash string.

To submit the generated prediction set:

Fill up your team info.
Choose output.txt.gz in Prediction File field.
Put content of md5.txt in MD5 Hash field.
Hit Submit button.

Soon you should receive emails with submission results ;)

There are several things which are not implemented in the current version:

processing cannot be stopped
estimator cannot be reloaded, so you should quit and start the app again if you changed the estimator

Technorati tags: netflix, netflixprize, netflix prize, varozhka, DIY

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Varozhka: Creating an estimator (part 3)

noreply@blogger.com (digizzle) — Fri, 15 Dec 2006 21:56:00 +0000

Overview

The same results can be achieved with Notepad and csc.exe from .NET Framework distribution, but I would recommend to use Visual Studio 2005 for that. I'm using VS2005 Standard Edition, but I'm pretty sure you can use any edition. If you don't have VS2005 installed - get your free copy of VS2005 Express Edition at http://msdn.microsoft.com/vstudio/express/.

Estimator creation

1. Run VS2005 and create a new Class Library project. Name the project as MyEstimator, and save it (say, to C:\Projects).

2. Add references to Varozhka.Processing.dll and Varozhka.TrainingData.dll assemblies. These assemblies located at the directory where you extracted the Varozhka package (C:\Varozhka).

3. Create a new class named as TestEstimator. Inherit the class from BaseEstimator class. It's an abstract class to set some constraints to descendant classes. Implement required constructor and override GetRating() method - this is a function where you have to implement your algorithm. For now let it return some constant value, say - 3.0.

The TestEstimator class should look something like:

     1 using System;
    2 using Varozhka.Processing;
    3 using Varozhka.TrainingData;
    4 
    5 namespace MyEstimator
    6 {
    7     public class TestEstimator : BaseEstimator
    8     {
    9         public TestEstimator(NetflixData netflixData) : 
   10                                         base(netflixData)
   11         {
   12         }
   13 
   14         public override float GetRating(int movieId, 
   15                                         int customerId, 
   16                                         DateTime date)
   17         {
   18             return 3.0f;
   19         }
   20     }
   21 }

Basically, the dumb estimator is ready, and you can use it in estimations... but we will try to create something more complicated.

4. Let's create an estimator which will return average rating of the customer. We should sum up ratings of all rated movies, and divide it by number of ratings. Our estimator contains NetflixData property, which gives access to Netflix information. In the current implementation it allows to get:

movies rated by user (GetMoviesByCustomer() method)
customer/rating pairs for a movie (GetPacksByMovie() method)
customer who watched a movie (GetCustomersByMovie() method). This method is pretty slow in the current implementation, and I would not recommend to use it.
rating of the movie by the given customer (GetRating() method).

Straightforward implementation will be:

    14 public override float GetRating(int movieId, 
   15                                 int customerId, 
   16                                 DateTime date)
   17 {
   18     // get all movies watched by the customer
   19     short[] movies = NetflixData.GetMoviesByCustomer(customerId);
   20 
   21     // get sum of all ratings
   22     int sumRatings = 0;
   23     foreach (short movie in movies)
   24     {
   25         sumRatings += NetflixData.GetRating(movie, customerId);
   26     }
   27 
   28     // calculate average rating
   29     return (float)sumRatings / (float)movies.Length;
   30 }

This implementation has several drawbacks. Say:

it will give wrong results for probe set, because we should ignore rating for movie with passed movieId.
it's a good idea to cache calculated movie ratings.

But the purpose of the sample is to show ability of indexes, so I'm ignoring these issues.

5. Compile the project in Release mode. Now we have working estimator, and it's ready to use in prediction generator ;)

Check the next post on how to generate predictions.

NOTE: the project is under development, so that will obsolete some day.

Technorati tags: netflix, netflixprize, netflix prize, varozhka, DIY

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Varozhka: Installation (part 2)

noreply@blogger.com (digizzle) — Fri, 15 Dec 2006 20:40:00 +0000

Requirements

Processing is very memory-consuming because the Netflix dataset is big enough. You need at least 1GB of RAM.
~3 GB of free space at HDD. Most of it is used by Netflix dataset.
Windows 2000/XP/2003/Vista. (checked on XP only. Please, let me know if you tried it on any other systems).
You need to have .NET Framework 2.0 installed. I guess everything (except the UI) can be migrated to Mono. Did not tried that though.

Preparations

First - download the archive with Netflix dataset. Extract it to some directory (say, c:\Netflix). Extract archive with movies (training_set.tar) to training_set subdirectory (c:\Netflix\training_set ) - this subdir is expected by indexer.

Installation

Download the latest version of Varozhka from SF.net.
Extract it to some directory (say, c:\Varozhka).

And now it's time to implement an estimator with your algorithm. Samples subdirectory (c:\Varozhka\Samples) contains two samples of simple estimators. You can view the code, or check walkthrough in the next post.

Technorati tags: netflix, netflixprize, netflix prize, varozhka, DIY

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Varozhka: Introduction (part 1)

noreply@blogger.com (digizzle) — Fri, 15 Dec 2006 20:08:00 +0000

As you may know, Netflix organized a competition for systems predicting user ratings for movies.

I'm sure a lot of bright people have ideas on how to improve that, but do not have time to spend on it.

This project is a framework to automate most of the dirty work with the dataset. So you can concentrate on the prediction algorithm ;)

Current features:

No additional DB engine is required. All indexes are loaded in memory.
Abstract layer to play with data (this is a place to plug in).
Data access layer.
Easy way to check RMSE against the probe set.
Generation of submission dataset.

So, basically you can download the Netflix dataset, extract it to a directory, start a wizard (which do all import tasks), implement your own rating estimator, and use a wizard to submit results to Netflix.

The project named Varozhka (belarusian word for "fortune-teller"). It hosted at Google Code and SourceForge.Net.

This is an introductory post about the project. More details later...

NOTE: The project is under development, and most of the code is not optimized in any way.

Technorati tags: netflix, netflixprize, netflix prize, varozhka, DIY

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NAnt 0.85 and active version of .NET Framework

noreply@blogger.com (digizzle) — Wed, 25 Oct 2006 20:19:00 +0000

By default, NAnt 0.85 (at least, RC4 I'm using) have .NET 2.0 Framework as active while running build scripts. And sometimes it's necessary to compile assembly (say, with <csc> task) for .NET 1.1 Framework. The info on how to change active .NET Framework is in the NAnt documentation, but some digging required to find it.

So here is a solution:

Technorati tags: nant, .net, build, howto

DIV stays empty after innerHTML assignment in Internet Explorer 6.0

noreply@blogger.com (digizzle) — Sun, 22 Oct 2006 20:19:00 +0000

I guess I'm not the first one who run into it, but I did not found a solution in the google. So here is the problem and my solution...

Problem
There is an empty DIV, which is located in hidden outer DIV ('display' is 'none'). On some event (say, click) - outer DIV became visible, and innerDIV.innerHTML assigned to some string. It works perfectly for FF, but in IE the inner DIV stays empty. Nevertheless, Internet Explorer Developer Toolbar shows that DIV content was changed and visible.

This is how it looks like in simplified code:
HTML:

JavaScript (with Prototype library 1.5.0_rc0):

Element.show('outer');
$('inner').innerHTML = 'foo';

Solution:
For the inner DIV I assigned style with height:100%, and it helped.
CSS:

#inner
{
height: 100%;
}

Note: Somehow I cannot reproduce the problem with some simple test, so maybe I missed something.

Technorati tags: IE, JavaScript, webdev

Wix 3.0: "tallow.exe" gone...

noreply@blogger.com (digizzle) — Tue, 17 Oct 2006 20:15:00 +0000

I decided to try WiX 3.0 (3.0.2128.0) for my current project. And here is a first issue (with help file) I run into:
I needed to generate information about files to install. It appears that WiX 2.0 contained an utility named "tallow.exe" to enumerate a directory and generate WiX Fragment for it. But the installed version of WiX doesn't have the utility.
I did some searches, but without success - everyone referencing to "tallow.exe". I started to examine all executables in bin directory, and finally found exactly what I need - "heat.exe" utility.
So... it appears "tallow.exe" was superseded by "heat.exe". Also "heat.exe" can generate fragments about a website, but I did not tried that one.
Here is a command line to generate a WiX fragment with files information:

C:\Program Files\Windows Installer XML v3\bin>heat.exe dir D:\src\bin\ -out c:\files.wxs

I guess it will be in WiX documentation soon, but not yet...

Technorati tags: wix, installer, msi, setup

Application Settings for Windows Forms .NET 2.0

noreply@blogger.com (digizzle) — Sun, 27 Aug 2006 17:23:00 +0000

Application Settings in .NET 2.0 allows to a developer to concentrate on real tasks, and not re-implement settings handling for every new application.

I did not have any experience with Application Settings, but with help of Visual Studio (it automatically generates all required stuff), it took five minute to add settings to an application.

The only problem was to get settings from previous version(s) of application. So it was time to load MSDN and read the documentation :)

ApplicationSettingsBase class has almost everything for the task: migration should be performed right after the settings was loaded, so it can be performed in handler of SettingsLoaded event. And Upgrade method allows to automatically migrate settings.

So all you need to do is to add a special boolean setting IsFirstRun with default value as true, and in SettingsLoaded handler call Upgrade if IsFirstRun is false.

Here is a snippet from Settings.cs (it should be generated by Visual Studio):

internal sealed partial class Settings
{
public Settings()
{
  SettingsLoaded += new SettingsLoadedEventHandler(Settings_SettingsLoaded);
}

void Settings_SettingsLoaded(object sender, SettingsLoadedEventArgs e)
{
  if (IsFirstRun)
  {
   Upgrade();
   IsFirstRun = false;
  }
}
}

Utility to convert ASP.NET sitemap to Google sitemap

noreply@blogger.com (digizzle) — Sat, 26 Aug 2006 18:31:00 +0000

Google sitemaps is a way for webmaster to notify Google about site changes. A website created with ASP.NET 2.0 also could contain a sitemap with navigation structure of the site. And, basically, both sitemaps are containing the same urls, but in different formats.

I needed a tool to generate Google sitemap from ASP.NET sitemap. I searched for such utility, but did not find what I need, so I created one. The utility is open-sourced (BSD license). I registered project at both Google Code and SourceForge, but Subversion hosted at Google Code. (BTW, do you know that SF.net now allows to use third-party SVN hosting?).

Download

SelectedDate property of Calendar control (ASP.NET 2.0)

noreply@blogger.com (digizzle) — Tue, 01 Aug 2006 18:58:00 +0000

Another day, another trick...
Spent a while in attempts to select a specific date in ASP.NET Calendar control. And it appears SelectedDate property is ignoring assigned value if it's not a midnight of the day. Date property of DateTime class is useful for that.

Here is a snippet:

_calendar.SelectedDate = DateTime.Now.Date;

PostBack and selection in DropDownList control (ASP.NET 2.0)

noreply@blogger.com (digizzle) — Mon, 31 Jul 2006 18:34:00 +0000

Sometimes a simple task can take plenty of time. And today I tried to use DropDownList control without ViewState (in other words - by "manually" populating the combobox on each page loading). By some reason, DropDownList control is not raising SelectedIndexChanged event if EnableViewState is False, and I'm not sure how to do it properly in ASP.NET way...

As workaround I used the control-name/value pair for the drop-down which is passed in HTTP POST parameters (when form is submitted). Control-name is UniqueID property of the drop-down, and the value contains the selected item.

So to restore the selection I used:

_combo.SelectedValue = Request[_combo.UniqueID];

Let me know if you know a better solution.

Compiling boost 1.33.1

noreply@blogger.com (digizzle) — Sun, 23 Jul 2006 18:38:00 +0000

Today I decided to update the boost library on my machine. And I got a strange error in attempt to compile Boost.Jam (bjam):

G:\boost_1_33_1\tools\build\jam_src>build
\Utilities\Bin\x86 was unexpected at this time.

The problem was solved after (temporary) removing the following path
from PATH environment variable:

H:\Program Files\Microsoft DirectX 9.0 SDK (October 2005)\Utilities\Bin\x86;

Seems like build.bat (or callee of it) do not like scopes in the PATH.

Cleaning up web cache for Visual Studio 2003

noreply@blogger.com (digizzle) — Mon, 10 Jul 2006 21:28:00 +0000

Web cache in Visual Studio 2003 (maybe in VS2002 as well) can give you some unpleasant moments. In my case, two branches of the same project behave differently if you compile them manually, and unexpectedly similar if compiled automatically (by NAnt). The reason of the problem was a cached assembly...

Visual Studio 2003 saves cached versions of your web projects in Web Cache directory. And if you are getting strange errors while opening your project, maybe it worth to clean up the cache.

The cache usually located at C:\Documents and Settings\username\VSWebCache. The path can be customized, and stored in registry under
HKCU\Software\Microsoft\VisualStudio\7.1\WebProject\OfflineCacheDir.

Here is a small NAnt snippet to cleanup web cache (VSWebCache) for the current user. It takes path to the cache from the registry, and delete the whole directory for the current user.

NOTE: you'll lose some of you user settings of your web projects, but automatic build will work correctly. But be sure you know what are you doing ;)

 <readregistry property="vs_web_cache" key="Software\Microsoft\VisualStudio\7.1\WebProject\OfflineCacheDir" hive="CurrentUser">

<delete dir="${path::combine(vs_web_cache, environment::get-machine-name())}" failonerror="false">

Flash player and textboxs in Firefox

noreply@blogger.com (digizzle) — Wed, 05 Jul 2006 01:30:00 +0000

Problem

Open a HTML page with a textbox and Flash Player in Firefox (FF1.5 and FP8.0). The textbox became locked if you hit Stop button in the Flash Player. It looks like focus is still in the text box, but it's impossible to type anything.
The same page works fine in Internet Explorer 6.0.

Solution

It's not mine solution, I found it here http://www.easterndesigner.com/forum/viewtopic.php?t=87. The solution was for another problem, but it works for locked textboxes as well.

You should set wmode as transparent in object's params and in attributes for embed tag. Also embed should be styled as style="z-index:inherit".

So the final code should looks something like:

<object classid="clsid:d27cdb6e-ae6d-11cf-96b8-444553540000"
 codebase="http://fpdownload.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=8,0,0,0"
 width="300" height="200" align="middle" >
 <param name="movie" value="foo.swf" />
 <param name="quality" value="high" />
 <param name="wmode" value="transparent" />
 <embed src="foo.swf" wmode="transparent" quality="high" width="300"  height="200" style="z-index:inherit" align="middle"  type="application/x-shockwave-flash"  pluginspage="http://www.macromedia.com/go/getflashplayer" />
</object>

Atlas ASP.NET - using external web services

noreply@blogger.com (digizzle) — Wed, 14 Jun 2006 21:00:00 +0000

The sample created with Atlas April 2006 CTP, so the example might be obsolete someday. And remember - it's just one from several different ways to achieve the same results.
"Atlas" allows to access external web services, but it took for me a while to create a working application. And I decided to write a walkthrough for it. The purpose of the walkthrough is to show how to access the web service with less code as possible, so - no error checking. As a test web service I choose GeoIPService - it detects country by IP address.
You can download sources for the walkthrough here (6 KB). The archive doesn't contain Atlas dll, so you should add it yourself to the Bin directory.

Preparation

In Visual Studio 2005 create a new web site using Atlas web site template:

From the created project delete unnecessary stuff (readme.txt, etc).

Server-side modifications

To access an external web service: a web application is accessing its home server, and the home server is accessing the external web service. That process named bridging. So let's create a bridge first.

Generate server-side code for web service calls:
1. Add App_Code ASP.NET folder (right-click on the project in Solution Explorer, Add ASP.NET folder \ App_Code).
2. Launch VS2005 Command Prompt.
3. In the console go to App_Code folder.
4. Execute "wsdl.exe http://www.webservicex.net/geoipservice.asmx?WSDL".
  It will generated a strongly-typed proxy for the web service.
5. Add generated class (GeoIPService.cs) to the project under the App_Code folder.
Add a wrapper for the generated code. The wrapper class is simple - it creates an instance of the generated GeoIPService class, and perform a call to its method:

public class GeoIPWrapper { public GeoIP LookupIP(string ip) { GeoIPService service = new GeoIPService(); GeoIP geoIP = service.GetGeoIP(ip); return geoIP; } }
The wrapper is not accessible directly from javascript code. To access it a bridge should be declared. So create xml file, and save it to the root of the project as GeoService.asbx. Content of the file should be:

<?xml version="1.0" encoding="utf-8" ?> <bridge namespace="AtlasTests" className="GeoService" > <proxy type="GeoIPWrapper, App_Code" /> <method name="LookupIP"> <input> <parameter name="ip" /> </input> </method> </bridge>

Client-side modifications

Open Default.aspx, and switch to Source view.
All changes will be done in this file, but I tried to separate changes logically.

Changes in HTML part

Add a reference to the web service bridge in the ScriptManager definition.

<atlas:ScriptManager ID="_scriptManager" runat="server"> <Services> <atlas:ServiceReference Path="~/GeoService.asbx" /> </Services> </atlas:ScriptManager>
Add an edit box to enter an IP address.

<input type="text" id="_boxIP" />
Add Lookup button to initiate a call to the web service from the client-side. In onclick handler add a call to JavaScript function (the function will be defined soon).

<input type="submit" id="_btnLookup" onclick="LookupIP(); return false;" />
Add an empty DIV block for results.

<div id="_results"></div>

Changes in JavaScript part

Add a script section.
Define variables for the edit box and results placeholder:

var _boxIP = new Sys.UI.TextBox($("_boxIP")); var _placeholder = new Sys.UI.Label($("_results"));
Implement LookupIP() function, it will make a call to the bridge. It's asynchronous call, so most parameters are callbacks.
First parameter is a dictionary with <key, value> pairs - in our case it contains only one pair. Second parameter is a callback to receive results. Third parameter - a callback which will be called on timeout. Fourth parameter - a callback for errors. There are other parameters (onMethodAborted, userContext, timeoutInterval, priority, useGetMethod), but they are ignored in this walkthrough.

function LookupIP() { var ip = _boxIP.get_text(); AtlasTests.GeoService.LookupIP({'ip': ip}, OnGeoResults, OnTimeout, OnError); }
Main callback is OnGeoResults() function. It receives an object with structure that is mirroring the structure returned by the web service.

function OnGeoResults(results) { // if succeeded if (results.ReturnCode == 1) { var strResult = "IP: " + results.IP + "<br/>Country: " + results.CountryName; _placeholder.set_text(strResult); } else { _placeholder.set_text(results.ReturnCodeDetails); } }

Two other callbacks are just stubs to notify us about critical situations.

function OnTimeout(result, context) { alert("Timeout! " + result.get_message()); } function OnError(result, response, context) { alert("Error! " + result.get_message()); }

Tests

Now we have a web application which can call external web services. The application is simple, so tests are simple as well. :)

Start the web application.
Enter some valid IP address (remember, there are no error checking).
And hit Lookup button.
If everything is OK you should get information about the IP address:

Empty table cells and Internet Explorer

noreply@blogger.com (digizzle) — Wed, 10 May 2006 02:33:00 +0000

Now I understand why cross-browser development is the experience mostly.
In nonogram I needed an empty cell (TD HTML object) with fixed size, and the cell can have several different backgrounds. And I'm building the table on fly with JavaScript.
I'm doing all testing in FireFox, and I was surprised after I checked the game in IE and Opera - empty cells don't have borders.
I tried to use CSS method - "empty-cells: show;", it helped with Opera, but not with IE.
I tried to put nbsp in the cell - size of cell became larger than I wanted.
I put 1x1 transparent gif in each cell, that helped, but it took around 8 seconds to load/render the table in IE (1.5 sec in FF).

So the current solution is to have a small char in the cell, say '.', with the same color as background of the cell. And set the cursor for cells as "cursor: default;".

Loading and rendering times now are:
3 sec in IE, 0.85 sec in FF and 0.4 sec in Opera.
Speed is still slow, but more acceptable. Maybe it makes sense to generate the table on server side.

I still not sure how it will work with older versions of browsers. :)