Update: On June 20th 2009, Codeplex notified me that the patch I did for the ACT has been applied. I haven't tested it yet, though. Get the latest source (not latest stable version) and you should be fine.
The Ajax Control Toolkit has a PopupExtender module that is used throughout the library in whichever controls need to show above other controls. I wanted to use the Calendar Extender in my web site, but the calendar appeared underneath other controls. I checked it out and it had a zIndex of 1000, which should have been enough. I took me an hour to realise that in the toolkit code zIndex was a property of the div element, not of the div style!
A download of the latest version from Feb 29 shows the problem is still there. The fix? go to the PopupExtender folder in the source code, open the PopupBehaviour.js file, search for a line that looks like this:
I am going to quickly describe what happened in the briefing, then link to the site where all the presentation materials can be found (if I ever find it :))
The whole thing was supposed to happen at the Grand RIN hotel, but apparently the people there changed their minds suddenly leaving the briefing without a set location. In the end the brief took place at the Marriott Hotel and the MSDN people were nice enough to phone me and let me know of the change.
The conference lasted for 9 hours, with coffee and lunch breaks, and also half an hour for signing in and another 30 minutes for introduction bullshit. You know the drill if you ever went to one of such events: you sit in a chair waiting for the event to start while you are SPAMMED with video presentations of Microsoft products, then some guy comes in saying hello, presenting the people that will do the talking, then each of the people that do the talking present themselves, maybe even thank the presenter at the beginning... like a circular reference! Luckily I brought my trusted ear plugs and PDA, loaded with sci-fi and tech files.
The actual talk began at 10:00, with Petru Jucovschi presenting as well as holding the first talk, about Linq and C# 3.0. He has recently taken over from Zoltan Herczeg and he has not yet gained the necessary confidence to keep crouds interested. Luckily, the information and code were reasonably well structured and, even if I've heard them before, held me watching the whole thing.
Linq highlights:
is new in .NET 3.0+ and it takes advantage of a lot of the other newly introduced features like anonymous types and methods, lambda expressions, expression trees, extension methods, object initializers and many others.
it works over any object defined as IQueryable<T> or IEnumerable (although this last thing is a bit of a compromise).
simplifies our way of working with queries, bring them closer to the .NET programming languages and from the just-in-time errors into the domain of compiler errors.
"out of the box" it comes with support for T-Sql, Xml, Objects and Datasets, but providers can be built (easily) for anything imaginable.
the linq queries are actually execution trees that are only run when GetEnumerator is called. This is called "deffered execution" and it means more queries can be linked and optimised before the data is actually required.
in case you want the data for caching purposes, there are ToList and ToArray methods available
Then there were two back-to-back sessions from my favourite speaker, Ciprian Jichici, about Linq over SQL and Linq over Entities. He was slightly tired and in a hurry to catch the plain for his native lands of Timisoara, VB, but he held it through, even if he had to talk for 2.5 hours straight. He went through the manual motions of creating mappings between Linq to SQL objects and actualy database data; it wouldn't compile, but the principles were throughly explained and I have all the respect for the fact that he didn't just drag and drop everything and not explain what happened in the background.
Linq to SQL highlights:
Linq to SQL does not replace SQL and SQL programming
Linq to SQL supports only T-SQL 2005 and 2008 for now, but Linq providers from the other DB manufacturers are sure to come.
Linq queries are being translated, wherever possible, to the SQL server and executed there.
queries support filtering, grouping, ordering, and C# functions. One of the query was done with StartsWith. I don't know if that translated into SQL2005 CLR code or into a LIKE and I don't know exactly what happends with custom methods
using simple decoration, mapping between SQL tables and C# objects can be done very easily
Visual Studio has GUI tools to accomplish the mapping for you
Linq to SQL can make good use of automatic properties and object initialisers and collection initialisers
an interesting feature is the ability to tell Linq which of the "child" objects to load with a parent object. You can read a Person object and load all its phone numbers and email addresses, but not the purchases made in that name
Linq to Entities highlights:
it does not ship with the .NET framework, but separately, probably a release version will be unveiled in the second half of this year
it uses three XML files to map source to destination: conceptual, mapping and database. The conceptual file will hold a schema of local object, the database file will hold a schema of source objects and the mapping will describe their relationship.
One of my questions was if I can use Linq to Entities to make a data adapter from an already existing data layer to another, using it to redesign data layer architecture. The answer was yes. I find this very interesting indeed.
of course, GUI tools will help you do that with drag and drop operations and so on and so on
the three level mapping allows you to create objects from more linked tables, making the internal workings of the database engine and even some of its structure irrelevant
I do not know if you can create an object from two different sources, like SQL and an XML file
for the moment Linq to SQL and Linq to Entities are built by different teams and they may have different approaches to similar problems
Then it was lunch time. For a classy (read expensive like crap) hotel, the service was really badly organised. The food was there, but you had to stay in long queues qith a plate in your hand to get some food, then quickly hunt for empty tables, the type you stand in front of to eat. The food was good though, although not exceptional.
Aurelian Popa was the third speaker, talking about Silverlight. Now, it may be something personal, but he brought in my mind the image of Tom Cruise, arrogant, hyperactive, a bit petty. I was half expecting him to say "show me the money!" all the time. He insisted on telling us about the great mathematician Comway who, by a silly mistake, created Conway's Life Game. If he could only spell his name right, tsk, tsk, tsk.
Anyway, technically this presentation was the most interesting to me, since it showed concepts I was not familiar with. Apparently Silverlight 1.0 is Javascript based, but Silverlight 2.0, which will be released by the half of this year, I guess, uses .NET! You can finally program the web with C#. The speed and code protection advantages are great. Silverlight 2.0 maintains the ability to manipulate Html DOM objects and let Javascript manipulate its elements.
Silverlight 2.0 highlights:
Silverlight 2.0 comes with its own .NET compact version, independent on .NET versions on the system or even on operating system
it is designed with compatibility in mind, cross-browser and cross-platform. One will be able to use it in Safari on Linux
the programming can be both declarative (using XAML) and object oriented (programatic access with C# or VB)
I asked if it was possible to manipulate the html DOM of the page and, being written in .NET, work significantly faster than the same operations in pure Javascript. The answer was yes, but since Silverlight is designed to be cross-browser, I doubt it is the whole answer. I wouldn't put it past Microsoft to make some performance optimizations for IE, though.
Silverlight 2.0 has extra abilities: CLR, DLR (for Ruby and other dynamic languages), suport for RSS, SOAP, WCF, WPF, Generics, Ajax, all the buzzwords are there, including DRM (ugh!)
The fourth presentation was just a bore, not worth mentioning. What I thought would enlighten me with new and exciting WCF features was something long, featureless (the technical details as well as the presenter) and lingering on the description would only make me look vengeful and cruel. One must maintain apparences, after all.
WCF highlights: google for them. WCF replaces Web Services, Remoting, Microsoft Message Queue, DCOM and can communicate with any one of them.
If you don't want to read the whole thing and just go to the solution, click here.
I reached a stage in an ASP.Net project where a I needed to make some pages work faster. I used dotTrace to profile the speed of each form and I optimized the C# and SQL code as much as I could. Some pages still were very slow.
Now, I had the idea to look for Javascript profilers. Good idea, bad offer. You either end up with a makeshift implementation that hurts more than it helps, or with something commercial that you don't even like. FireFox has a few free options like FireBug or Venkman, but I didn't even like them and then the pages I was talking about were performing badly in Internet Explorer, not FireFox.
That got me thinking of the time when Firefox managed to quickly select all the items in a <select> element, while on Internet Explorer it scrolled to each item when selecting it, slowing the process tremendously. I then solved that issue by setting the select style.display to none, selecting all the items, then restoring the display. It worked instantly.
Most ASP.Net applications have a MasterPage now. Even most other types of sites employ a template for all the pages in a web application, with the changing page content set in a div or some other container. My solution is simple and easy to apply to the entire project:
Step 1. Set the style.display for the page content container to "none". Step 2. Add a function to the window.onload event to restore the style.display.
Now what will happen is that the content will be displayed in the hidden div, all javascript functions that create, move, change elements in the content will work really fast, as Internet Explorer will not refresh the visual content in the middle of the execution, then show the hidden div.
A more elegant solution would have been to disable the visual refresh of the element while the changes are taking place, then enable it again, but I don't think one can do that in Javascript.
This fix can be applied to pages in FireFox as well, although I don't know if it speeds anything significantly. The overall effect will be like the one in Internet Explorer table display. You will see the page appear suddenly, rather than see each row appear while the table is loaded. This might be nice or not nice, depending on personal taste.
Another cool idea would be to hide the div and replace it with a "Page loading" div or image. That would look even cooler.
Here is the code for the restoration of display. In my own project I just set the div to style="display:none", although it might be more elegant to also hide it using Javascript for the off chance that someone might view the site in lynx or has Javascript disabled.
function addEvent(elm, evType, fn, useCapture) // addEvent and removeEvent // cross-browser event handling for IE5+, NS6 and Mozilla // By Scott Andrew { if (elm.addEventListener){ elm.addEventListener(evType, fn, useCapture); return true; } else if (elm.attachEvent){ var r = elm.attachEvent("on"+evType, fn); return r; } else { alert("Handler could not be removed"); } }
function initMasterPage() { document.getElementById('contenuti').style.display=''; }
Ok, so I used a javascript script in my page by referencing the external file and it worked. I did the exact same thing with another file and it wasn't loading! After scratching my head bald I've decided to switch the places of the two tags and voila! the script that worked would not load! The one that did not work previously was purring nicely.
After scratching my skull a little more (blood was dripping already) I realized that the script tags are atomic tags, they should have no ending tag. Why would they, the content is specified in the src attribute. But on the DOM page for the script element there is an obscure line saying: Start tag: required, End tag: required. I switched to <script></script> format and it worked.
Oh, you are wondering why the first script worked? Because somehow an atomic script tag is erroneous, but it doesn't return any error. Instead it is treated like a mistyped start tag and the atomic portion of it is ignored. The second script would not load since the browser expected a script end tag. Maybe he even interpreted the second tag as an end tag for all I know.
Apparently, the innerText property of Javascript elements is not available for FireFox or other browsers other than Internet Explorer. FireFox exposes something similar, but with the name textContent. Why would any one of these two butt-heads learn from the other and cooperate for the common good?
The functionality of this property is to expose the inner content of an element minus any html tags. With something like <div><span class="red">Red text<span></div> the div innerText/textContent property returns "Red text". It could also work when setting, stripping tags from the content before setting innerHTML, although it seems that for both implementations setting innerText or textContent is equivalent with setting innerHTML.
There are also links about javascript functions that would replace, improve or otherwise ease the developer's work by adding the same functionality.
I was asked to fix a bug and I soon found out that the "bug" was actually IE's regex split implementation! You see? When you split by a string, the resulting array does not contain any empty spaces found!
Ex: 'a,,b'.split(/,/) = ['a','b'] in IE and ['a','','b'] in FireFox.
Searching the web I found this very nice page from regular expression guru Steven Levithan: JavaScript split Inconsistencies & Bugs: Fixed!. You can also find there a link to a page that tests the issues with your browser's Javascript regex.
Bottom line! Use Steven's code to regex split in Javascript.
I was looking for ways of speeding up my web pages, considering that one utility page I built reached 500Kb and from that, only 170kb where actually content, the rest was Javascript. Bad Javascript, I accept, but it works, ya know?
So, after thinking and thinking I thought of a novel approach to this: how about googling for it? and I found this very nice and comprehensive article: Speed Up Your Javascript Load Time.
Before Asp.Net Ajax was released I used to work with a library called AjaxPro (formerly Ajax.Net). It also wrapped specially decorated methods and sent them to the Page as javascript functions with a callback javascript function as the last parameter. In this library, by not using a callback you were saying that you want to execute the function synchronously, that you want to wait for a result. After all, that's a functionality included in the XmlHttpRequest object.
I was amazed to see that Asp.Net Ajax does not offer such an option. You NEED a callback function. So... how do you use a WebMethod as a javascript validation function, since the validators only accept a synchronous function?
The first idea I had was the easy way, to cycle inside the function until I had a result. Bad idea: Javascript itself is not really multitask, so it just took the CPU to 100% and that was the end of it: kill task. The second idea was the hard way: redo all code in the XmlHttpRequest wrapper and use the included synchronous functionality. Too complicated, although I found an article about how to do that. So here is the way I did it: 1. Get the validator object 2. Set a property on it to tell if the validator is inside an async call or not 3. Set a property to hold the last value that was validated 4. Set a property to hold the last result returned 5. Set a method of the validator as the call back function 6. If is in async return false 7. If the last value is the same with the current validating value, return last result 8. Execute the async validation function with the validator callback method as a parameter and return false (or "in async")
Now, the callback method just sets the result and clears the async flag and also updates the visual of the validator. By doing this I essentially don't allow postbacks during validation calls, which makes sense. I also had an idea of creating a special "in async" validator that would not allow postback and would display something nice, but the solution I am explaining keeps it local, with ValidationGroups and everything working just fine.
I will show the code in a few seconds, but first be warned that I am using a validator made by myself which expects null or true as valid and a string or false as invalid. If the result is a string, it displays it as the ErrorMessage. So, on with the code: The function to get a reference to the validator (which in some cases, especially Ajax, is not the same as the span with the same id)
function getValidator(id) { if (typeof(Page_Validators)=='object') for (c=0; c<Page_Validators.length; c++) if (Page_Validators[c].id==id) return Page_Validators[c]; return false; }
The preparing function, which can be reused for more validators. I couldn't find a better way to encapsulate this behaviour yet, please feel free to enlighten me with ideas
// parameters are the value to be validated // and the validator object function prepareAsync(value,validator) { if (!validator) { validator.doReturn=true; return 'Error in prepareAsync: validator not found!'; } // it's validating if (validator.inAsync) { validator.doReturn=true; return 'In async validation'; } // it has validated this value before if (validator.prevValue==value) { validator.doReturn=true; return validator.result; } // create the callBack function as a method // of the validator object if (!validator.callBack) validator.callBack=function(res) { validator.inAsync=false; validator.result=res; if (res==null) { validator.isvalid=true; } else if (typeof(res)=='boolean') { validator.isvalid=res; } else { // setting the validation message is // as simple as changing the innerHTML // of the validator span validator.innerHTML=res; validator.isvalid=false; } // that's an ASP.Net validator function // since .NET 1.0 upwards ValidatorUpdateDisplay(validator); } validator.inAsync=true; validator.prevValue=value; validator.doReturn=false; }
and now a sample validation function:
// parameters are the value to be validated // and the id of the validator function ValidateProdotto(value,id) { // get the validator object var validator=getValidator(id); // reuse this function to all validators in the page var res=prepareAsync(value,validator); // doReturn says if it has a result for us if (validator.doReturn) return res; // perform the actual validation PageMethods.ValidateProdotto(value,validator.callBack); // and return false, since we are in async now return false; }
Hope this helps somebody. This applies to short validations, but feel free to enhance my design with cancellations of running async operations in case the value is changed or with an array caching all the values tried and validated.
Ok, the why is something I could never truly understand. It's some lawyer thing. But the fact remains that Microsoft was legally bound to show that message on each ActiveX control in Internet Explorer, thus screwing everybody and all their Flash pages.
When you Google this you find a miriad solutions. Some of them rewrite the entire HTML, others just take all the objects and embeds and rewrite their innerHTML or their outerHtml. But sometimes, it just seems that none of them work. And here is the catch for all of them: in order to work, the function that does the replacing of the HTML must be in an external Javascript file. Yes, you read right, if the function is inside the page, it doesn't work. Weird, huh?
Anyway, here is the script I use. It works, apparently.
Update: Well, I noticed that the Flash file I wanted to use stopped working after using this fix. Luckily I had the source and so I found a fix. The next post details it.
It all started with my own library, a dll in which I wanted to include Javascript, CSS and ultimately images or flash files. I did it the only way I could in 1.1, mainly adding the resources to the project, setting them as Embedded Resource, then reading them and either put them in the page or write them in the application directory and link them in the page. As you can imagine, there were a lot of issues related to writing writes and so on.
But then .NET 2.0 and the AjaxControlToolkit arrived. This toolkit had this funny looking Tab thing, and it used images. So where did it get the images? I was surprised to see that the namespace of the TabContainer control was decorated with stuff like this:
Could it be so easy? yes! And for the js files, they had this class called a ScriptControlBase and the only thing you needed to do to insert a javascript file was decorate the implementing class like this:
These three articles pretty much explain the basics, so I won't do anything but emphasize the more important points:
When you use the name of the resource, either when decorating the namespace or when getting the reference to it, use the project namespace and the folder in which the file is in, otherwise it will not work. So if you have the namespace MyControls.Web and you have the folder Images in which you embedded an Image.gif file, the name should be MyControls.Web.Images.Image.gif.
To programatically get the url for an embedded resource use Page.ClientScript.GetWebResourceUrl(Type type,string resourceName)
In order to get the contents of an embedded resource use code like this:
Assembly assembly = GetType().Assembly; arr = assembly.GetManifestResourceNames(); foreach (string name in arr) if (name==resourceName) { Stream s = assembly.GetManifestResourceStream(name); // do something with the stream break; }
But what is this WebResource.axd? It's an IHttpHandler, one that you can also implement quite easily. They are used to handle Ajax, file uploads, get access to all kinds of resources. Look it up. Somewhere in the near future I might write an article about these, too.
Update: in IE7 I noticed that the style property doesn't keep the inherited values or the CSS values, but only the inline values of style. 'currentStyle' keeps all values, therefore I used that too, in case style would not work.
Update: the same can be done in FireFox by using the document.defaultView.getComputedStyle(myObject, null) syntax equivalent to myObject.currentStyle in Internet Explorer. I have not updated my function to work with that, though.
Update: By adding a break in case of relative or absolute positioning I seemed to have fixed most of the issues regarding those types of positioned elements.
Whenever one wants to popup something with Javascript, the bigger problem arising is to find the absolute position of the element that you want the popup to cling to. Searching the web you will probably find a site like this: How to get an element’s position and area, you will try that solution and say "Wee! It works!" until you scroll something inside the page and everything turns to mush.
Analysing the code and the html you will see that it ignores completely the scrolling of various elements. Even worse, the offsetParent is one for Internet Explorer and another for FireFox. So here is my solution, which seems to work in most cases. I will work on it some more, but not in the near future and usually one doesn't need a popup in a popup. So here is the code:
function findPos(obj) { var curleft = 0; var curtop = 0; if (obj.offsetParent) { while (obj.offsetParent) { curleft += obj.offsetLeft-obj.scrollLeft; curtop += obj.offsetTop-obj.scrollTop; var position=''; if (obj.style&&obj.style.position) position=obj.style.position.toLowerCase(); if (!position) if (obj.currentStyle && obj.currentStyle.position) position = obj.currentStyle.position.toLowerCase(); if ((position=='absolute')||(position=='relative')) break; while (obj.parentNode!=obj.offsetParent) { obj=obj.parentNode; curleft -= obj.scrollLeft; curtop -= obj.scrollTop; } obj = obj.offsetParent; } } else { if (obj.x) curleft += obj.x; if (obj.y) curtop += obj.y; } return {left:curleft,top:curtop}; }
Yesterday I was trying to make one of my controls keep its scroll position. Since you can't set a scrollTop attribute (which I think it is dumb, but that's another issue) I used a HiddenField and some Javascript. Mainly one at submit that loaded the scrollTop value in the hidden field and one on load to re-set it.
Since the logic of my control was mainly in the Render method of the control, I wrote the RegisterStartupScriptBlock and RegisterOnSubmitStatement lines there. It worked like a charm, but then I decided to see if it works WITHOUT Ajax.Net by removing the update panel I have been using. It failed!
I wasted like two hours before I understood that the RegisterOnSubmitStatement did not add anything to the page. I moved it in the OnPreRender method of the control and it worked!
So, long story short: DO NOT use RegisterOnSubmitStatement in the Render method of controls, as I believe the onsubmit (and possibly ClientScriptBlocks) are rendered by the page before any of the controls on it.
I've updated this page a few times, adding more optimizations, so get the last version.
I was asked to find a way to maintain the vertical scroll in a selection box (that is a select html element with a size bigger than 1). I checked to see what property was changing when I was scrolling the select and I noticed that scrollTop was the one. So I used
sel.scrollTop=value;
.
Well, this works fine in FireFox and apparently works fine in IE7, too. However, in Internet Explorer 7, if you click on the up/down arrows of the select scrollbar, the scroll resets to 0. Worst than that, in IE6 you can't even set the scrollTop property. You don't get an error, but it doesn't work.
One suggested solution for people that tried the same thing is to set the size attribute to the number of options, thus getting rid of the select scrollbar, and place the select in a div with fixed height and overflow auto. It will look like a select listbox, but the scroll will be from the div and easily changed. I didn't choose this solution, basically because I felt it was cheating.
So, I've applied another solution, one that changes the selected item so that the select element scrolls itself to a position as close to the desired vertical scroll position as possible. Then, I set the scrollTop property, so that it goes at that exact position in IE7 and FireFox. If one clicks the up/down scroll arrows in IE7, the scroll position resets to the one found by the selectedIndex, not 0. And it works in IE6, too.
Here is the code:
Warning! This will not work if the select is hidden by way of display=none or visibility=hidden. Also, for large selects, it will look funny scrolling through all the options. Optimizations can be applied, that try to find the correct selectedIndex or stop after the scroll position has been found (like in this example) or that search the best scrollTop match by dividing the options in two parts rather than taking them one by one, etc.
Warning: this is only a partially working solution due to some Javascript issues described (and solved) here.
A requirement I had was to maintain the scroll position of ListBoxes on PostBack. The only solution I could find was to get the scroll through Javascript (the scrollTop property of the select) and restore it on page load, however, that would have meant a lot of custom controls, not to mention lots of work, to which I am usually against.
So, I used a ControlAdapter! The ControlAdapter is something new to the NET 2.0 framework. The Control in 2.0 looks for a ControlAdapter and delegates the usual methods (like OnLoad,OnInit,Render,etc) to the adapter. You tell the site to use an adapter for a specific type of control and possibly a specific browser type (by using a browser file), and it uses that adapter for all of the controls of the selected type and also the ones inherited from them. To disallow the "adaptation" of your control, override ResolveAdapter to always return null.
Ok, the code!
Of course, you will ask me What is that ScriptManagerHelper? It's a little something that tries to get the ScriptManager class without having to reference the System.Web.Extensions library for Ajax. That means that if there is Ajax around, it will use ScriptManager.[method] and if it is not it will use ClientScript.[method]. To.Int(object) is obviously something that gets the integer value from a string.
There is another thing, at the beginning I've inherited this adapter from a WebControlAdapter, but it resulted in showing all the options in the select (all the items in the ListBox) with empty text. The value was set as well as the number of options. It might be because in WebControlAdapter the Render method looks like this:
I was looking for an answer to the problem of a grid inside an update panel. You see, since the rows and cells of a DataGrid or a GridView are special controls that can't be put inside panels, only in specific parent controls like tables and rows, there is no way to update only a row or a cell of a grid. If the grid is big, it takes a long time to render it entirely, it takes the CPU to 100%, it even blocks the animation of gifs. That results in ugly Ajax.
So, my first thought was: is there a way to update only what has changed? As I was saying in a previous post, a Page is rendered as its HTML string the first time it is loaded and then each Ajax postback makes it render like a list of tokens. The token format is this:
length|type|id|content|
For example 100|updatePanel|UpdatePanel1|<inner HTML of panel of 100 bytes>|
What if I would to insert my own tokens, then? Could I, let's say, change the innerHTML of a control outside of the UpdatePanel? And the answer is YES!
There are 20 token types:
updatePanel
hiddenField
arrayDeclaration
scriptBlock
expando
onSubmit
asyncPostBackControlIDs
postBackControlIDs
updatePanelIDs
asyncPostBackTimeout
childUpdatePanelIDs
panelsToRefreshIDs
formAction
dataItem
dataItemJson
scriptDispose
pageRedirect
error
pageTitle
focus
Most are not interesting, but 4 of them are!
type:updatePanel If you add a token to the rendered page string that has the typeupdatePanel and the id is the UniqueID or ClientID of a control, the content will replace the innerHTML of that control, even if the control is not in an UpdatePanel.
type:hiddenField If you add a token to the rendered page string that has the typehiddenField and the id is the UniqueID or ClientID of a control, the content will replace the value html property of that control. You can use it on hidden fields, but also on any type of input or html element that has a value. If the control does not exist, a hidden input will be created with that id and then the value will be set. You could read that value after a normal PostBack, let's say.
type:expando If you add a token to the rendered page string that has the typeexpando a script will be executed in Javascript that looks like this:
id=content
Example: 5|expando|document.getElementById('TextBox1').style.backgroundColor|'red'| This will result in the change of the background color of the control with id TextBox1 to red.
type:focus If you add a token to the rendered page string that has the typefocus and the content is a ClientID, then the focus will be set to that control provided that the focus.js script has been loaded. This script is loaded when you use Page.SetFocus. So, in order to set the focus to a control using this method, you must use SetFocus in PageLoad on any control you would like.
Why not use SetFocus, then, and be done with it? Well, because this, as all the methods above work on ANY control in the page, not just the ones in the update panel.
Of course, that doesn't solve my initial problem, of speeding up the Ajax rendering of large grids. That's because, even if I would solve the ViewState issues and the quirks that are bound to appear, I still can't change the innerHTML property of tables or table rows, as it is a readonly property.
So where am I to use this? It's easy: first of all, put a button (and only a button) inside an UpdatePanel. Any click on that button will trigger an Ajax postback, but will send a minimal amount of data. Then, put outside the UpdatePanel a Panel. Now you can override the Render of the page and on every Ajax postback, add whatever HTML you want to that panel. If you want to do it from javascript, put the button in a div with style="display:none" and then trigger the button click whenever you want to cause the postback. I am certain that for large readonly grids, that is a way faster method than the putting the grid inside the updatepanel.
To do this the traditional Atlas way you would have had to declare a web service, and then to set a javascript onclick event on the button, that would have executed a WebService method that returned a string, and manually change the innerHTML of the panel.
Update: On June 20th 2009, Codeplex notified me that the patch I did for the ACT has been applied. I haven't tested it yet, though. Get the latest source (not latest stable version) and you should be fine.