Thursday, October 30, 2008

Sorting LInQ results in a GridView

I had this really old site that I was asked to "upgrade". Net 1.1 to 3.5. So I had to change old ADO.Net SqlConnection to Linq-to-Sql. A lot of unforseen issues. Sometimes it is close to impossible to recreate a simple SQL query without changing the database, as in the case of updating tables or views without primary keys.

Anyway, I got stuck in a very simple issue: How to sort a Linq query based on the string returned by the GridView Sorting event. After a lot of tries and Googling I found it was easier to use third party software (although it's more of a 2.5rd party software, as it is made by Scott Guthrie from Microsoft). Here is the link to the blog entry: Dynamic LINQ (Part 1: Using the LINQ Dynamic Query Library) . You can find there a sample project to download, with the LINQ Dynamic Library inside.

With this library and the OrderBy extension methods the code becomes:
var somethings=from something in db.Somethings....;
var data = somethings.OrderBy(Sort + " asc");
gv.DataSource=data;
gv.DataBind();

Friday, October 24, 2008

Globalization and Localization for AjaxControlToolkit controls

I had this calendar extender thingie in my site and the client was Italian so I had to translate it into Italian. Nothing easier. Just enable EnableScriptGlobalization and EnableScriptLocalization and set either the Web.config or Page culture settings.

However, the footer of the calendar kept showing "Today" instead of "Oggi". I checked the source and I noticed that it used a AjaxControlToolkit.Resources.Calendar_Today javascript variable to create the footer. Step by step I narrowed it down to the AjaxControlToolkit resources! Funny thing is that they didn't work. I tried just about everything, including Googling, only to find people having the opposite problem: they would have all these resource dlls created in their Bin directory and couldn't get rid of them. I had none! I copied the directories from the ACTK and nothing happened.

After some research I realized that the Ajax Control Toolkit does NOT include the option for multi language UNLESS in Release mode. I was using everything in the solution, including the ACTK, in Debug mode. Changing the AjaxControlToolkit build to Release in the solution made this work.

Tuesday, October 21, 2008

Reinvention, a bad or a good thing?

A new (and old) buzzword: to reinvent. It is always a good thing to reinvent yourself, they say, with the effect of relieving boredom and living a "new" life. You may discard bad or useless things in favor of good things. It is also good to reinvent something somebody else did, like a movie. You take the idea, you remove the bad things, you add good things. But, as in the case of the benevolent tyrant, the definition of good and bad is always fuzzy.

Was it good to reinvent BattleStar Galactica? I say YES! It was (and still is, despite screenwriters efforts) the best sci-fi series out there. Of course, that is my opinion. Was it good to reinvent Terminator, incarnated into a teenage girl looking machine? Ahem. But I still watch it. Was it good to reinvent Superman as a troubled teenager? Puh-lease! Come... on! Nah-uh! (See, I address the younger demographic here).

Because, you see, the people that decide what is good and bad in movies are actually the money people. They look at superficial statistics that only show... money! They make abhorent remakes of decent films (like Indiana Jones 4 - The Rape of Indiana) or they turn every hero into man/woman/teenager/animated-character/doll versions that bring nothing new.

The original vs. the reinvented crew In the case of Star Trek, they made the first low budget series than achieved cult level regardless of bad production values and some ridiculous scripts, then they made a sequel (at that time reinvention was not invented yet) where Patrick Stewart redefined the space captain as a cerebral science oriented man, but with lots of guts, then they started the old routine: make the captain black, make him a woman, replace the ship with a station, then with another ship, but in some other place, etc. They even made a prequel, which, for almost a full season, was decent in both interpretation and scenarios. What was missing, of course, was a teenage Star Trek captain. Well, no more!

"Star Trek", the 2009 movie in the making (and no doubt, with a series looming if money are made), features a young Kirk and (what a fallacy) a young Spock! The director is none other than my least favourite person in the world: J.J.Abrams, the maker of such abismal stupidities (but well received by the general audience) like Alias, Lost and Fringe. The writers are Abramses old team, Roberto Orci and Alex Kurtzman, the brilliant creators of such idiocies like Alias, Fringe and Xena/Hercules!

I am trying to keep an open mind here, but I would venture to guess that the new Star Trek will have big booming sounds whenever something strange happends, will be filled with inexplicable things that will never be explained, except maybe in the movie (but I doubt it, they have to plant the hook for a series) and will have people calling the others by name obsessively, regardless if the need for it arises. So, it may be cool, but I expect to be baktag!

Monday, October 20, 2008

Path Vol.2 - Apocalyptica feat. Sandra Nasic (Guano Apes)

I've listened to this song for a long time now, it was only proper that it would appear on my blog sooner or later. Sandra Nasic sang for Guano Apes and after the band split she released a solo album in 2007 called The Signal which features some good songs, although a little mellow for my taste. You can listen to fragments of some of Sandra's songs on her MySpace site, visit her official site or just plain google for videos like I do :)

So listen to this symphonic Sandra Nasic sound. I wish she would have done more pieces like this.


Saturday, October 18, 2008

Brisingr by Cristopher Paolini (Eragon 3)

Book cover Brisingr is the third book in the Inheritance cycle (now a cycle because the author could not end the story in only three books). While I enjoyed reading it and I know that Paolini had all the best intentions writing it, I would not recommend it.

I have too little recollection of the first two books, to tell you the truth, but I do remember I was captivated by the action in them, if nothing else. The "magical technology" also had a great lure for me. In the third installment, all of these are missing or of poor quality. Roran is far more interesting than Eragon in this book, while the bad characters have lost a few dimensions (from the few they already had) and have become pathetic. T'Pol (sorry... I meant Arya) is docile and closer to the human heart, making her completely uninteresting, while the elves in general (and Oromir and Glaedr in particular) act like Asgaard on pot.

Why use StarTrek and StarGate terms to describe a fantasy book? Because it seems that's the only real inspiration of the third book of the Inheritance cycle. I could have done without the Doctor Who references in it, as well.

You can see a little YouTube video of Christopher Paolini talking about Brinsgr here, where an "unofficial" fan club is trying to earn money from said YouTube by disabling the embedding option.

Friday, October 10, 2008

AutoCompleteExtender with images (or any kind of template)

A few days ago a coworker asked me about implementing an autocomplete textbox with not only text items, but also images. I thought, how hard can it be? I am sure the guys that made the AutoCompleteExtender in the AjaxControlToolkit thought about it. Yeah, right!

So, I needed to tap into the list showing mechanism of the AutoCompleteExtender, then (maybe) into the item selected mechanism. The AutoCompleteExtender exposes the OnClientShowing and the OnClientItemSelected properties. They expect a function name that accepts a behaviour and an args parameters.

Ok, the extender creates an html element to contain the list completion items or gets one from the property CompletionListElementID (which is obsoleted anyway). It creates a LI element for each item (or a DIV in case of setting CompletionListElementID). So all I had to do was iterate through the childNodes of the container element and change their content.

Then, on item selected, unfortunately the AutoCompleteExtender tries to take the text value with firstChild.nodeValue, which pretty much fails if the first child of the item element is not a text node. So we will tap in OnClientItemSelected, which args object contains item, the text extracted as mentioned above (useless to us), and the object that was passed from the web service that provided the completion list. The last one we need, but keep reading on.

So the display is easy (after you get the hang of the Microsoft patterns). But now you have to return a list of objects, not mere strings, in order to get all the information we need, like the text and the image URL. Here is the piece of code that interprets the values received from the web service:
// Get the text/value for the item
try {
var pair = Sys.Serialization.JavaScriptSerializer.deserialize('(' + completionItems[i] + ')');
if (pair && pair.First) {
// Use the text and value pair returned from the web service
text = pair.First;
value = pair.Second;
} else {
// If the web service only returned a regular string, use it for
// both the text and the value
text = pair;
value = pair;
}
} catch (ex) {
text = completionItems[i];
value = completionItems[i];
}


In other words, it first tries to deserialize the string received, then it checks if it is a Pair object (if it has a First property) else it passes the object as value and text! If deserialization fails, the entire original string is considered. Bingo! So on the server side we need to serialize the array of strings we want to send to the client. And we do that by using System.Web.Script.Serialization.JavaScriptSerializer. You will see how it goes into the code.

So far we displayed what we wanted, we sent what we wanted, all we need is to set how we want the completion items to appear. And for that I could have used a simple string property, but I wanted all the goodness of the intellisense in Visual Studio and all the objects I want, without having to Render them manually into strings.

So, the final version of the AutoCompleteExtender with images is this: A class that inherits AutoCompleteExtender, but also INamingContainer. It has a property ItemTemplate of the type ITemplate which will hold the template we want in the item. You also need a web service that will use the JavascriptSerializer to construct the strings returned.

Here is the complete code:
AdvancedAutoComplete.cs

using System;
using System.IO;
using System.Web.UI;
using System.Web.UI.WebControls;
using AjaxControlToolkit;

namespace Siderite.Web.WebControls
{
/// <summary>
/// AutoCompleteExtender with templating
/// </summary>
public class AdvancedAutoComplete : AutoCompleteExtender, INamingContainer
{
private ITemplate _template;

[TemplateContainer(typeof(Content))]
[PersistenceMode(PersistenceMode.InnerProperty)]
public ITemplate ItemTemplate
{
get { return _template; }
set { _template = value; }
}

protected override void OnInit(EventArgs e)
{
base.OnInit(e);
const string script = @"
function AdvancedItemDisplay(behaviour,args) {
var template=behaviour.get_element().getAttribute('_template');
//if (!template==null) template='${0}';
for (var i=0; i<behaviour._completionListElement.childNodes.length; i++) {
var item=behaviour._completionListElement.childNodes[i];
var vals = item._value;
var html=template;
for (var c=0; c<vals.length; c++)
html=html.replace(new RegExp('\\$\\{'+c+'\\}','g'),vals[c]);
item.innerHTML=html;
}
}

function AdvancedSetText(behaviour,args) {
var vals=args._value;
var element=behaviour.get_element();
var control = element.control;
if (control && control.set_text)
control.set_text(vals[0]);
else
element.value = vals[0];
}
"
;
ScriptManager.RegisterClientScriptBlock(this, GetType(), "AdvancedAutoComplete", script, true);

OnClientShowing = "AdvancedItemDisplay";
OnClientItemSelected = "AdvancedSetText";
}

protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
string template = GetTemplate();
((TextBox)TargetControl).Attributes["_template"] = template;
}

private string GetTemplate()
{
Content ph=new Content();
ph.Page = Page;
_template.InstantiateIn(ph);
HtmlTextWriter htw = new HtmlTextWriter(new StringWriter());
ph.RenderControl(htw);
return htw.InnerWriter.ToString();
}
}
}


MainService.cs

using System.Collections.Generic;
using System.Web.Script.Serialization;
using System.Web.Script.Services;
using System.Web.Services;

/// <summary>
/// Web service to send auto complete items to the AdvancedAutoComplete extender
/// </summary>
[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[ScriptService]
public class MainService : WebService
{
[WebMethod]
[ScriptMethod]
public string[] GetCompletionList(string prefixText, int count)
{
JavaScriptSerializer jss=new JavaScriptSerializer();
List<string> list=new List<string>();
for (int c = 0; (list.Count< count) && (c < 100000); c++)
{
string s = (c*c).ToString();
if (s.StartsWith(prefixText))
{
object[] item = new object[] {s, "images/demo.gif"};
list.Add(jss.Serialize(item));
}
}
return list.ToArray();
}
}



An example of the use

<asp:TextBox runat="server" ID="tbMain"></asp:TextBox>
<cc1:AdvancedAutoComplete ID="aceMain" runat="server" BehaviorID="mhMain" TargetControlID="tbMain"
ServiceMethod="GetCompletionList" ServicePath="~/MainService.asmx" MinimumPrefixLength="0"
CompletionInterval="0">
<ItemTemplate>
<asp:Image runat="server" ID="imgTest" ImageUrl="${1}" /><asp:Label runat="server"
ID="lbTest" Text="${0}"></asp:Label>
</ItemTemplate>
</cc1:AdvancedAutoComplete>


That's it! All you have to do is make sure the controls in the template render ${N} text that gets replaced with the first, second, Nth item in the list sent by the web service. The text that will be changed in the textbox is always the first item in the list (${0}).

Restrictions: if you want to use this a control in a library and THEN add some more functionality on the Showing and ItemSelected events, you need to take into account that those are not real events, but javascript functions, and the design of the autocompleteextender only accepts one function name. You could create your own function that also call on the one described here, but that's besides the point of this blog entry.

Thursday, October 09, 2008

Monday, October 06, 2008

Zodiac by Neal Stephenson

Book coverZodiac is an environmental eco-thriller. It's Stephenson's second novel and it started in a similar way to The Big U, which I couldn't really read through. But I had nothing else to read so I kept going until it got funny and good. If you read it, try to get over the bad start, because it is not a bad book at all.

The basic plot is that of a pragmatic environmentalist with a chemistry background working against the waste dumping industry. In the end he uncovers a plot of global implications and, of course, foils it. But the story itself is more important than the ending. This is not one of those books you read in half a day, driven by the need to know how it all turns out, but one of those you read waiting to see what the main character is going to do or say next, while going towards the predictable finish.

Here is a much better commentary than mine, what I can say is that the book was definitely not sci-fi, rather a thrill-fiction, but it was well written. It makes for a good train book.